the kinetics of drug–membrane interactions in human erythrocytes

The kinetics of drug-membrane interactions in human erythrocytes

SINIKKA ESKELINEN Department oJ'Bhq,sic~Iogy, University of Oulu, Kujmnintie 52A, SF-98220 Oulu, Finland

Received December 10. 1986

ESKELINEN, S. 1987. The kinetics of drug-membrane interactions in human erythrocytes. Can. 9. Pkysiol. Phamacol. 65: 2373-2378.

The time course of the shape transfornations and vesicle release in human erythrocytes caused by lysophosphatidylcholine and chlorpromazine was monitored using a light microscope - video recording technique. The time required for the erythrocytes to reach a stage I echinocytic shape decreased from 4.0 to 2.0 s. when the concentration of the Iysophosphatidylcholhe solution injected was increased from 1 to 25 $LM. The time required to reach stage I1 decreased from 8.3 to 3.5 s and that required for vesicle release and the formation of stage IV spherocytes decreased from 78.0 to 1 1.6 s . Correspondingly, the time needed for the formation of stage I stomatocytes decreased frorn 2.3 to 1.0 s and that for stage IH stomatocytes from 3.1 to 2.0 s . when the ambient chlorpromazine concentration was increased from 50 to 200 pM. The kinetics of the shape transformations of the erythrocytes were dependent on the ambient drug concentration. The rate of shape trsnsfomtions courd be predicted from a formula derived for the kinetics of the incorporation of the detergent into the cell membrane, providing that the affinity coefficient and mass transfer coefficient for drugs changed as a function of the free drug concentration. The results give a time scale for the drug-membrane interactions, i.e., the formation of stages I and I1 for drug-lipid bilayer interactions and the release of vesicles for drug-cytoskeleton interactions.

ESKELINEN, S . 1987, The kinetics of drug-membrane interactions in human erythrocytes. Can. 9. Physiol. Pharmacol. 65 : 2373-2378.

On a observe, dans des erythrocytes d'hurnains, I'kvolution t e m p o d e des transformations ~alorphologiques et de la liberation de v&icules, induite par la lysophosphatidylchdine et Ba chlorpromazine. en utilisant une technique d'enregistrement video au microscope optique. Le temps nkcessaire aux krythrocytes pour acquerir la f o r m kchinocytique du stade I a diminu6 dc 4,0 a 2,0 s, lorsque la concentration de la solution de lysophosphatidylcholine injectbe a et6 augmentke de 1 2 25 pM. Le temps requis F u r atteindre le stade I1 a diminud de 8.3 a 3,5 s et celui requis pour la libkration des vCsicules et la formation de sphkrocytes du stade IV, de 7#,0 A 11,6 s. Par consequent, le temps nkcessaire pour la formation de stomatocytes du stade I a diminuk de 2,3 B 1,O s et ceiiui pour les stcmatocytes de stade I1 de 3, l 2 2.0 s, lorsque la concentration de chlorpromazine utiliske a kt6 augment& de 58 B 208 pha Les cinitiqucs des transformations de formes des drytkrscytes ktaient, par consdquent, fonctions de la concentration de la drogue utiliske. Le taux de transformation de formes pouvait etre calculi selon m e fornule obtenue pour les einCtiques de l ' incopration du detergent dans la membrane celhlaire, 2 condition de varier les coefficients d'affiniti et de trarasfert de masse pour les drogues en fonction de la concentration de drogue libre. Les resultats etablissent une 6cheBle de temps pour les interactions drogue-membrane, c.-a-d., la formation dc stades I et I1 pour les interactions drogue-double couche lipidique et la libiration dc vQicules pour les interactions drogue-cytosquelette.

[Traduit par la revue]

Lipid-soluble agents, anaesthetics, and tranquilizers are in- corporated into the cell membrane (Bondy and Remien 198 1; Klibansky and deVries 1963; Kwant and Seernan 1969; Roth and Seeman 1972; Roth et al. 19721, the binding of the detergent being related to the cell concentration in the suspension (Welt- zien et al. 1997) and to the detergent concentration (Bondy and Remien 198 1 ; Klibansky and deVries 1963; Kwant and Seeinan 1969; Roth and Seeman 1972; Roth et al. 1972). Binding experiments usua$ly entail incubation of the cells with the drug solution for 10-38 min to reach an equilibrium (Kwant and Seenlan 1969; Tanmeera et al. I984). The shortest times reported have been 1-2 min for the incorporation of lysophosphatidylcholine (LBC) or its analogues into the erythrtxyte membrane to the point of equilibrium (Klibansky and deVries 1963; Weltzien et al. 1977) and 1 nrin for chBorpromazine (CPZ) (Bondy and Remien 198 1 ) . The detergents influence the membranes almost instantaneously; however, the shape transformations of erythrocytes to echinocytes or stomatocytes caused by detergents take pIace within a few seconds of contact with the drug (Flmjii et ale 1984; Nagasawa-Fujirnori et al. 1981) and intravenous anaesthetics reach the brain only a matter of tens of seconds after intravenous injection (Price et al. l96O).

The light-scattering stopped-flow method has been used to monitor the time course sf shape transformations of erythrocytes to echinocytes or stomatocytes (Nagasawa-Fujimori st al. 1981) classified as stage 1 or I1 according to Fujii e t a%. (1979); but it does not detect the further sequences of shape transfoma- aims to stage 111 echinocytes or stomatocytes or vcsicle release

and the forrnation of spherocytes (stage IV), for which purpose light microscopy is needed. A new method for observing cell respnses to sudden changes in their environment under a light microscope (Eskelinen and Coakley 1986) is used to study the kinetics of the shape transfornation and vesicle release of human erythrocytes under the influence of LPC or CPZ. The major emphasis is focused on canelations between the ambient detergent concentrations and the kinetics of the shape transformations to distinguish the kinetics of drug incorporation from the membrane reorganization caused by the drugs, which is of importance for understanding the action of anaesthetics or tranquilizers at cell membranes. Part of this work has been pub- lished in abstract form (Eskelinen 1986).

Materials and methods h! merids

Human erythrocytes from five volunteers were obtained by finger puncture and collected in an isotonic phosphate-buffered saline solution (153.2 mM NaCl, 5.8 inM sodium phosphate, pH 7.4) to an approximate concentration of 5 X 1 o7 celBs/PPlk (Hct. 0.5%).

LPC, having 18 carbon atoms in the acyl chain (frorn Sigma Chemi- cal Co.) was dissolved in absolute ethanol to a 5 mh1 concentration (2.5 rng/mE) and diluted to the desired concentrations with an isotonic NaCl scdution. CPZ (Sigma Chemical Co.) was dissolved in an isotonic NaCl solution to 100 nA4 concentration and diluted with the same medium.

Video recording ~fshupe frmsformations Changes in cell morphology were observed microscopically using a

x40 objective and a video recording system (Eskelinen and Coakley

Prmted In ('anada ! Impnmt' du Canada

Can

. J. P

hysi

ol. P

harm

acol

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Uni

vers

ity o

f A

uckl

and

on 1

1/09

/14

For

pers

onal

use

onl

y.

23'94 CAN. J . PHYSIBL. PKIARMACOL. VOL. 65, 1987

FIG. I . Video recording showing various stages of shape transfcmnaaions of human erythrocytes after 16 p M LPC solution in isotonic saline had been injected into the cell suspension. The nulnbcrs show the time in seconds following the beginning of the injection. Most of the cells have reached stage I in (bIl stage 11 in (c) , and stage IV in (e )

1986). Glass microcapillaries of rectangular cross section (with inter- nd dimensions of 2 ram wide and 8.2 mrn high, Micrdides . Camlab Etd., U.K.) were pre-cleaned by boiling in a surfactant solution fol- lowed by multiple rinses in boiling water to prevent "glass-effect" and - - - - - -

the echinscyToiiis cdf i5rj7tlar%y tcs; as previcmdy &scribe& by &dcy and Co&ley (1983).

A quantity of the cell suspension was drawn into the microcapillary by capilia-y forces, and the loaded nnicrocapillay was placed on a microscope slide with its long axis perpendicular to that of the microscope slide. The ambient medium sf the cells in the microcapillary on the slide under the microscope was changed by injecting a new solution containing the drug from a small rectangular microcapillary connected to a microsyringe and Inserted into the larger microcapillary containing the cells, as described by Eskelinen and Coakley (1986). The outer width of the small microcapillary was 0.6 mrn and its thickness, 0.15 mm: the internal dimensions were width, 0.5 mm and height, 0.05 nam. Prior to insertion into the larger microcapiillargr, the tip of the smaller one had k e n narrowed by thermal extrusion to internal dimensions uf ( I 00- 150) pm X ( 1 5-20] p m so that the injection current of the ncw medium would have a diameter many times wider than that of a cell (Eskdinen and Coakley 1986).

Thc experiments involved bringing into focus the cells in the isotcmis solution in a microcagiIlary, whereupon video recording was stated. Injection of a detergent solution was begun and continued for 3 anin. All the experiments were carried out at room temperature.

T h e measaremenbs The video films were analyzed by measuring the time elapsing from

the beginning of the detergent injection to the fortnation of the various shape stages (Fujii et al. 1979) in individual cells. A slight movement of every cell at the moment of the contact with the new medium was used as a zero point far time measurements of that particular cell. All the measurements were repeated twice and the mean value was used. The times required for the shape tramsfosnnations caused by various concentrations of LPC or CPZ were analyzed statistically using Kolmo- gorov's test for normality and Bartlett's test for the equivalence of

variances connected with Student's f-test for thc equivalence betwcen the means.

Results M z m m r d t h s - - - - - - - - - - - - - - - - - - - - - - - - - -

The sequence of events during echinocytosis and vesicle release sf erythrocytes owing to the injection of 16 yM LPC is illustrated in Fig. 8 . The average periods required for single cells to change their shape to that of stage I o r stage 11 echino- eytes and stage IV spherocytes under the influence of various concentrations of LPC are shown in Table 1. The resolution of the video images was too low to observe the sharpening of the spicules, and hence the formation of stage HI1 echinocytes was not analyzed.

The sequence s f events during stomatocytosis owing to the injection s f 200 pM CBZ is illustrated in Fig. 2. The average times needed for single cells to transform to stage I or stage II stomatocytes under the influence of \ arious concentrations of CPZ are shown in Table 2. The resolution was too low to accurately observe the slow foranatlon s f stage 11 stc~matocytes under the influence of 50 piM CPZ solution or to distinguish stages 1x1 and 1V.

Andyxis of r e s d s The concentration of the detergent in the cell membrane (car,,)

as a function of time ( t ) and ambient concentration ( ( a f l ) can be described as

where c,Fl,lax is the maximal drug concentration in the cell membrane; K is the affinity constant; q = k4/Vm; k is the mass transfer coefficient; A is the membrane area; and V,, is membrane

Can

. J. P

hysi

ol. P

harm

acol

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Uni

vers

ity o

f A

uckl

and

on 1

1/09

/14

For

pers

onal

use

onl

y.

ESMELINEN 2375

FIG. 2. Video recording showing various stages of shape transfomations of human erythrocytes after 200 FM CPZ solution in isotonic saline had been iaqected intea the cell suspension. The numbers show the time in seconds follcnving the beginning of the injection. Most of the cells have reached stage I in ( c ) and stage II in (6).

TABLE 1. Average times in seconds and standard error of the mean for the stages of the shape transformations after injection of various concentrations of LPC. The stages are classified accc~rding to Fujii et aI.

( 1979)

NOTE: N = number of cells counted. Tlme times required to reach stage I or HI under the influence of I yM LPC did not differ significantly Dom the corresponding ones with 8 FM LPC, and the tirnes required to reach stage I or I1 under the influence of I6 FM L,PC did not differ from those with 25 pM. In all other cases !he possibility of equi~lity of the mean vaimes tb the Pime penods was rejected ( y .:: 0.05).

volume (Bird et al. 1960; Mwant and Seeman B 969; Appendix I > .

Provided the following statements are valid, the experimental times from Tables 1 and 2 should satisfy eq. 1: (i) shape transfom~ations follow the kinetics of the incorporation of drugs into the membrane; (ii) the affinity coefficient (K), maximal membrane drug concentration (c-F'), mass transfer coefficient ( k ) . and hence y are constants; and (iii) the cells change their shape at a constant membrane concentration of the drug regard- less sf the extracellular level. Three groups of equations can be obtained in the case of LPC by inserting the times and ambient %PC concentrations from Table H into eq . I :

TABLE 2, The average times in seconds and standard error of the mean for thc stages of the shape transfomations after injection of various concentrations s f GPZ. The stages are classified aecord-

in2 to Fujii et al. (1 979)

Concentration of CPZ ( ~ m ) Stage I Stage 11

NOTE: ti = ~ ~ u m b e r d c e l l s counted. The possibility of equality of the mean values for the time periods was rejected in all cases ( p < 0.05).

for LPC stage I1

[3] c,,(stage I I ) lcFX = K( 1 - e-8 "q)/( l + K) &.,(stage II)/c-Af"" - 8KQ 1 - e-' "gq) / ( 1 + 8K) c,,(stage II)/c,",'" = 16K(8 - e-3.44q)/(l -+- 16fl

c,,(stage I 1 ) l ~ ~ ~ " .= 25R(I -e4."")l(1 + 25K)

Can

. J. P

hysi

ol. P

harm

acol

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Uni

vers

ity o

f A

uckl

and

on 1

1/09

/14

For

pers

onal

use

onl

y.

2376 CAN. J . PHYSIOL. PMARMACOL. VOL. 65 , 1987

TABLE 3. The theoretical affinity coefficients (K), theoretical coefficients (q) relative to the mass transfer coefficient (q = MIV,, k is the mass transfer coefficient; A is membrane area; and 8/,, is membrane volume), and the calculated ratios of the membrane LPG concentrations (c,,) to the maximal membrane concentration (c?) with various ambient LPC concentrations. The values s f Kand q were chosen so that the ratio c,/c,""" for a particular shape (stage I. 11, or IV) is independent of

the ambient EPC concentration

Stage I Stage I1 Stage IV Concentration of LPC (pM) K Y c r n / c ~ ~ K 4 c I n / c F K 4 c n a / ~ ~

TABLE 4. The theoretical affinity coefficients (0, theoretical coefficients (q) relative to the mass transfer coefficient (q = M!V,, k is the mass transfer coefficient; A is membrane area; and V , is membrane v c h n e ) , and the calculated ratios of the membrane GPZ concentrations (c,,) to the maximal membrane concentration ( c r ) with various ambient CPZ concentrations. The values of K and q are chosen so that the ratio cdc,",""" (35 or 70%) for a particular shape (stage I or 11) is independent of the ambient

CPZ concentration

Stage I Stage I1 Concentration of CPZ (pM) K Y c,Jc,":,X K 4 c,, J c z y

and for LPC stage IV

[4] c,(stage I V ) / c r = K(1- e-77."q)l(l 4- K ) - - €&stage lV)/r= = 8 ~ ( 1 ~ e - : ~ . ~ ~ : ) / ( l + 8x1

- - - - - - - -

~,(stage IV)/cTx = 16K(1 -e-'6N4)/(1 + 16K) c,,,(stage IV)/cCa" = 25K(1 -e-I '57q)/ ( l t 2 5 9

In addition to the trivial sdutlons c,, = O if K - 0 or q - 0, no other common solutions can be found for these three groups of equations. However, providing that each particular stage of shape transformation takes place with the same amount of given drug in the membrane as shown by Fujii and Tamura (1984) and Kanaho et al. (198 I), but K and q are not constant, the eqs. 2-4 can be solved (Table 3). The values of K, q, and c,lc,""" in Table 3 are theoretical, of course. They are, bwever , the only values that fulfill the following requirements: c , , / c ~ " is cnn- stant for a given stage with all the concentrations of LPC, and K and q are constant for at least one pair of ambient LPC concentrations for each stage of shapes.

The situation is similar with CPZ, for which two groups of equations can be written:

for CPZ stage %

151 c,(stage l ) / c y = 50K(1- ev2 26q)/i( 1 + 50K) c,,(stage Uc~~,""" = HOOK(1 -e-'.""q)l(l + IOOK)

cm(stage I)/cZax = 20Oq 1 - e-I 04q)/( 1 t 208K)

and for CPZ stage I1

161 c , ( s t a g e I I ) / ~ ~ ~ = 100IY(l-e-'-l'q)/(l 3- IO(3K) c,(stage II)/c,m"" = 200K(I - e-'.98')l( 1 f 200K)

but no common solution can be found. If K is kept constant, q must increase and vice versa, to fulfill the requirement of a constant value of c , l ~ , ~ ~ " , e.g., for stage I with various ambient CPZ concentrations. The numerical values of K and y, then, depena 6ntke vahe ~ c,fc:" .-An exaara+-oi%he udues4br q is given in Table 4, which gives c , / c F = 35% for stage 1 and c,,/czx = 78% for stage 11, when Kis kept constant (K = 0.165 p ~ - ' as measured by Kwant and Seernan 4 1969)).

Discussion The times required for transformation to stage I echinocytes

were longer than those observed by Fujii et al. (1984) in the presence of 1.5 pM LPC at room temperature using a light- scattering stopped-flow appamtus. These authors observed that shape transformations follow first-order kinetics with an apparent rate constant of 2.3 s-' for 18 carbon atoms in the acyl chain of LPC, which correspond to the composition of LPC used in the present work. This rate constant means that 90% of the LPC- induced change in light scattering occurs in 1.0 s, whereas the shortest time measured in the light microscopy experiments was 2.0 s (Table I). For 20 p M CPZ, the light-scattering experiments gave a rate constant of 20 s-I at 3 T C , which means that 98% of the cells change their shape to stage 1 in 0.12 s (Naga- sawa-Fujimori et aL 19$l), a time shorter than that observed in Table 2. The rate constant is nevertheless temperature dependent (Nagasawa-Fujimori et d . 1981) and the CPZ results are not directly comparable. The Bight-scattering change may be influenced by chug-induced changes in the Bight-scattering prop- erties sf the membrane as well as by changes in the cell shape (Nagasawa-Fujimori et al. 1981); this may explain the shorter times obtained by this method, in addition to interindividual

Can

. J. P

hysi

ol. P

harm

acol

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Uni

vers

ity o

f A

uckl

and

on 1

1/09

/14

For

pers

onal

use

onl

y.

variations. The light microscope method used in the present work has a Bower limit, approximately 0.3-0.5 s for the observations of cell responses; however, the measured times are far from this limit (Tables 1 and 2).

The kinetics of the shape transfomations of the erythrocytes were dependent on the ambient drug concentration, excluding the times required to reach stage I or I1 echinocytes under the influence of 1 or 8 pM LPC and of 16 or 25 FM LPC, which did not differ significantly from each other (Table I). The kinetics of changes in light-scattering intensity have also been observed to be dependent on the ambient fatty acid (Fujii et al. 1984) or CPZ concentration (Nagasawa-Fu~imori et a%. 198 1).

There are no experimental data on the mass transfer coefficients of LPC or CPZ in the literature. Therefore the analysis of measured kinetics of shape transformations on the basis of the equation derived for drug incorporation is only semiquantitative. The results show, however, the conditions when the eq. I holds and the measured times can be predicted by the kinetics of drug incorporation.

The calculated relative concentrations c~,/s,,""" for shape transformations caused by LPC (c , l c~(s tage I) : C , , I C ~ ~ ~ (stage 11) : c. , l~~"~(stage IV), 0.15 1 : 0.225 : 0.462 and 0.33 : 0.49 : 1.00) in Table 3 are quite consistent with the relative values for c, measured by Fuji and Tamura (1 984) (c,(stage I) : c,(stage 11) : c,,,(stage III), 73 nrnol110~~ cells : 124 n m o l l l ~ ' ~ cells : 220 n m ~ l l 1 ~ i ' ~ c e l l s and 0.33 : 0.56 : 1). The experimental vdues of c, for stage IV are missing. With ambient LPC concentrations from 8 to 25 pM the kinetics of shape transformations to reach stage I and stage II could be predicted by the equation derived for drug incorporation, providing that the coefficient K is constant, but q decreases with 25 pM LPC . This is consistent with the observations that the partition coefficients for neutral or negative anaesthetics are independent of the free drug concentration (Roth and Seeman 1972). With 1 pM LPC in the ambient medium, both the affinity coefficient and mass transfer coefficient were much larger than with higher LPC concentrations, showing that the shape transformations took place "too quickly" with I pM LPC solution (Table 3). The lowest concentration of LPC, I pM, used in the present work is below the critical micelle concentration (CMC) of LPC, but the higher concentrations are approaching or above CMC (Helenius and Simons 1975). Thus, with the higher LPC concentrations, there may be a delay in the incorporation of the drug to the membrane due to CMC + monomer transformation of LPC. For stage IV , q is decreased showing that the membrane area A , which is included in q = kAIV,,, is decreased (Table 3).

In the case of CPZ the kinetics of shape transformations could not be predicted by the kinetics of drug incorporation using constant values of K and q. Kanaho et al. (198 8 ) have shown that the shape transfomations to stages I and I1 stomritocytes require 0.41 and 0.80 pmol CPZImL cells, respectively. Thus, c,,(stage I) : c,,(stage 11) is 0.5 : 1 . In Table 4 an example is given how q must change if K is kept constant (K = 0.165 PM-' from Kwant and Seeman (1969)) and the ratio c,lc~"(stage I) : c,,lc,~P..(stage 11) is 0.5 : 1 . One can see that q must increase with increasing ambient CPZ concentrations to keep c , , l c ~ " constant for a given stage of shapes. The partition coefficient for CPZ has been shown to be constant with cfi < lOfa pM with a 10% haematocrit at 39°C (Kanaho et al. 1981) and between 50 and 100 pM ambient CPZ with a 10% haematocrit (Tamura et al. 1984), but decreasing sharply above 60 pM CPZ with a haematocrit value of 0.5% ((Bondy and Remien 1% 1). Also the affinity coefficient decreases with an increase in the free CPZ

concentration above 30 pM (Kwant and Seeman 1969). Hence, the mass transfer coefficient must increase even more with increasing CPZ concentration if K decreases in Table 4. The apparent increase in q suggests that shape transfomations with high ambient CBZ concentrations take place too quickly. This may indicate that there is a threshold CPZ concentration in the membrane that triggers the shape transformation, which thereaf- ter proceeds at its own speed independently of the membrane CPZ concentration. The critical micelle concentration of CPZ is 300 pM in an isotonic solution at 2 5 T (Ogiso et al. 1977). So the results should not be disturbed by changes in the drug aggregation in the medium.

With the method developed, it is possible to follow the kinetics of the influence of membrane-active drugs on the cell membrane, and the times measured in the present work give a time scale for drug-membrane interactions: the formation of stages I and I1 for drug-lipid bilayer interactions (Sheetz and Singer 1974) and the times for cells to release cytoskeleton-free vesicles and to transform into stage BV spherocytes (Haest 1982) for drug-cytoskeleton interactions; but the results are, of course, semiquantitative in nature.

Acknowledgements This work was supported by the Natural Science Research

Council of the Academy of Finland. I am indebted to Mr. Urpcs Kylmanen for the help in constructing the video recording system and to Dr. Juha Kortelainen for help with the computing problems.

Appendix 1 The flow J of the drug into the cell membrane as a function of time

can be described by

[ l A] J = dnlAdt = k(cfl - c,)

where n is the number of drug molecules in the membrane and is equal to c,V,,, (Bird et al. 1 %(I). Hence the change in the membrane concentration

The solution of eq. 2A is

According to eq. 3A the final equilibrium drug concentration in the cell membrane is the same as in the ambient medium: c., = cn at equilibrium. This is not the case in practice, however, and the final concentration in the membrane as a function of the ambient drug c~ncentration can be described best by

14A] c, (at equilibrium) - I + Kcn

where c,"= is the absolute maximal drug concentration in the cell membrane and K is the affinity constant (Kwant and Seeman 1969). Inserting this into eq. 3 4 a final formula is obtained for the concentration of the drug in the cell membrane as a function of time and ambient drug concentration:

where q = kA/V,,.

BIRD, R. B., STEWART, W. E., and LIGHTFOOT, E. N. 1960. Transport phenomena. John Wiley & Sons, inc., New York.

BONDY, B . , and KEMIEN, J. 198 1 . Differential binding s f cblorprorna- zine to human blood cells: application of the hygroscopic desorption method. Life SSc 22: 441-449.

Can

. J. P

hysi

ol. P

harm

acol

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Uni

vers

ity o

f A

uckl

and

on 1

1/09

/14

For

pers

onal

use

onl

y.

2378 CAN. J. PHYSIOL. PHARMACOL. VOL. 65, 1987

DEELEY, J. O. T., and COAKLEY, W. T. 1983. Interfacial instabilityand membrane internaiization in human erythrocytes heated in thepresence of serum albumin. Biochim. Biophys. Acta, 727: 293-302.

ESKELINEN, S. 1986. Kinetics of shape transformations and vesiclerelease of erythrocytes caused by LPC or CPZ. Vol. 11. Proceedingsof the Eighth School on Biophysics of Membrane Transport, Mierki,Poland, May 4-13, 1986. p. 267.

ESKELINEN, S., and COAKLEY, W. T. 1986. Microscopic observationand video recording of cellular response to sudden changes in en-vironment. J. Microsc. (Oxford), 141: 119-126.

FUJII, T., andTAMURA, A. 1984. Shape change of human erythrocytesinduced by phosphatidylcholine and lysophosphatidylcholine spe-cies with various acyl chain lengths. Cell Biochem. Funct. 2: 171-176.

FUJII, T., SATO, T., TAMURA, A., WAKATSUKI, M., andKANAHO, Y.1979, Shape changes of human erythrocytes induced by variousamphipathic drugs acting on the membrane of the intact cells.Biochem. Pharmacol. 28: 613-620.

FUJII, T., TAMURA, A., TANAKA, T., NAGASAWA-FUJIMORI, H., andHIROMI, K. 1984. Light scattering stopped-flow studies on the timecourse of shape changes induced in human erythrocytes by severalamphiphiliclipids. Biochem. Int. 8: 83-88.

HAEST, C. W. M. 1982. interactions between membrane skeletonproteins and the intrinsic domain of the erytlirocyte membrane.Biochim. Biophys. Acta, 694: 331-352.

HELENIUS, A., and SIMONS, K. 1975. Solubilization of membranes bydetergents. Biochim. Biophys. Acta, 415: 29-79.

KANAHO, Y., SATO, T., and FUJII, T. 1981. The affinity of variousphenothiazine drags for membranes of intact human erythrocytesand their membrane-transforming activity. Mol. Pharmacol. 20:704-708.

KLIBANSKY, C., and DEVRIES, A. 1963. Quantitative study of erythro-cyte-lysolecithin interaction. Biochim. Biophys. Acta, 70: 176—187.

KWANT, W. O., and SEEMAN, P. 1969. The membrane concentrationof a local anesthetic (chlorpromazine). Biochim. Biophys. Acta,183:530-543.

NAGASAWA-FUJIMORI, H., HIROMI, K., MORIWAKI, N., and FUJII, T.1981. Application of light scattering stopped-flow method to theobservation of rapid processes of shape changes of human erythro-cytes induced by various drugs. Biochem. Int. 2: 129-135.

OGISO, T., KUROBE, M., MASUDA, H., and KATO, Y. 1977. Effect ofdrugs on human erythrocytes. II. A possible mechanism of drug-induced hemolysis. Chem. Pharm. Bull. 25: 1078-1088.

PRICE, H. L., KOVNAK, P. H., SAFER, J. N., CONNER, E. H., andPRICE, M. L. 1960. The uptake of thiopental by body tissues and itsrelation to the duration of narcosis. Clin. Pharmacol. Ther. (St.Louis), 1: 16-22.

ROTH, S., and SEEMAN, P. 1972. The membrane concentrations ofneutral and positive anesthetics (alcohols, chlorpromazine, mor-phine) fit the Meyer-Overton rule of anesthesia; negative narcoticsdo not. Biochim. Biophys. Acta, 255: 207-219.

ROTH, S., SEEMAN, P., AKERMAN, S. B. A., and CHAU-WONG, M.1972. The action and absorption of local anesthetic enantiomers onerythrocyte and synaptosome membranes. Biochim. Biophys. Acta,255: 199-206.

SHEETZ, M. P., and SINGER, S. J. 1974. Biological membranes asbilayer couples. A molecular mechanism of drug-erythrocyte in-teractions. Proc. Natl. Acad. Sci. U.S.A. 71: 4457-4461.

TAMURA, A., SATO, T., and FUJII, T. 1984. Relationship betweendrug- and phospholipase-induced shape changes of human erythro-cytes. Chem. Pharm. Bull. 32: 1904-1911.

WELTZIEN, H. U., ARNOLD, B., andREUTHER, R. 1977. Quantitativestudies on lysolecithin-mediated hemolysis. Use of cther-deoxylysolecithin analogs with varying aliphatic chain-lengths. Biochim.Biophys. Acta, 466: 411-421.

Can

. J. P

hysi

ol. P

harm

acol

. Dow

nloa

ded

from

ww

w.n

rcre

sear

chpr

ess.

com

by

Uni

vers

ity o

f A

uckl

and

on 1

1/09

/14

For

pers

onal

use

onl

y.

the kinetics of drug–membrane interactions in human erythrocytes

Documents