institute of experimental medicine, budapest
DESCRIPTION
Institute of Experimental Medicine, Budapest. Brain mechanisms of PTSD. Glutamatergic plasticity and PTSD. Long-term effects of trauma exposure. Long-term effects of trauma exposure. Novel approches to PTSD. Cannabinoids in PTSD. József Haller. 1/22. "Incubation" phase (1-6 month). - PowerPoint PPT PresentationTRANSCRIPT
1/221/22
What is PTSD?
PTSD = Post-Traumatic Stress Disorder
An anxiety disorder that develops in response to strong stressors
Trauma "Incubation" phase(1-6 month)
The development of persistent symptoms
Early responseAcute
Stress Disorder
~1 month
Silent period
2/222/22
DSM-IV criteria for PTSDTriggering factor (Cluster A): traumatic event (1) life threatening (2) helplessReexperiencing the trauma (Cluster B) (1) distressing recollections (2) distressing dreams (3) reliving the experience by illusions, hallucinations, and dissociative flashbacks (4) psychological distress when faced with trauma-related cues (5) psychological distress when faced with trauma-related cuesAvoidance and numbing (Cluster C) (1) avoiding trauma-related thoughts, feelings, or conversations (2) avoiding trauma-related activities, places, or people (3) inability to recall an important aspect of the trauma (4) diminished interest in significant activities (5) detachment from others (6) restricted range of affect (7) sense of a foreshortened futureHyperarousal (Cluster D) (1) sleep problems (2) irritability (3) difficulty concentrating (4) hypervigilance (5) exaggerated startle response Duration is more than 1 month (Cluster E)
Number of symptoms "required" within a cluster2
2
3
2
1
How does it look like? Is it simply anxiety?
It usully lasts years or decades
Trauma(life-threatening stress)
re-experiencing
avoiding cue-associated cues
hyperarousal
+ psychosis depression violence drug addiction anxiety, etc.
A single exposure to a traumatic stress induces a dramatic worsening of in psychological functioning
A remarkable example of neuronal plasticity
3/223/22
Certain profesions (ambulance)
Assaultive violence
Diabetes, children
and in their mothers
and in their mothers
Forced migration
AIDS
Family violence
Trafic accidents, children
Terrorist attack
Natural disaster (earthquake)
Combat
likelyhoodTrauma in mothers, PTSD in child
How important it is? Risk factors and risks
0 10 20 30 40 50 60 70
Prevalence of PTSD (%)
80 90 100
Risk factor
Average
0
2
4
6
8
10
1 2 3 4
Study Nr.5 6 7 8
Pre
vale
nce
of
PT
SD
in
th
e g
ener
al p
op
ula
tio
n (
%)
Prevalence in the general population
Factors prenatal stress early life stress traumatic stressors in adulthood
General perception: People in general are not at risk. I'm safe.
Factors leading to PTSD are parts of daily life
Certain stressors predictably lead to PTSD
similar to the prevalence of other anxiety disorders
Breslau et al., 1991; Breslau et al., 1999; Clohessy and Ehlers, 1999; Creamer et al., 2001; Goowin and Davidson, 2004; Kessler et al., 1995; Landolt et al., 2005; Marshall et al., 2005; Olley et al., 2005; Perkonnig et al., 2000; Resnik et al., 1993; Rosenman, 2002; Seedat et al., 2005; Shalev and Freedman, 20054/224/22
Unemployment
How does it develop? Glutamatergic plasticity
0
100
200
oppo
nent
tim
e (s
ec) 300
0
5
10
Kontroll
cat exposure24 h earlier
0.05 0.1 mg/kg MK-8010open
arm
exp
lora
tion
(%tim
e)
15
*
Adamec et al., 1999Haller et al., 2006
a
Kontroll 0.05 0.1 mg/kg MK-8010
electric shock24 hours earlier
bb
a
Trauma Behavioral deficitsplasticity of
glutamatergic neurotransmission
The blockade of NMDA receptors by MK-801 blocks the development of trauma-related deficits
5/225/22
Treatment
NMDA blockers are highly debilitating and addictive ("angel dust")
Trauma
serotonin
-
SSRIs
-
serotonin
plasticity of
glutamatergic neurotransmission
plasticity of
glutamatergic neurotransmissionBehavioral deficitsBehavioral deficits
alpha 1 or beta blockers
+
noradrenalin
a
b
Sham
c
a
b
0
100
200
oppo
nent
tim
e (s
ec) 300
5-HTx NAx xx
Serotonin and noradrenaline modulate
but not mediatetrauma-induced deficits
Problems with these treatments less well tolerated than placebo efficacy: significant but often poor certain symptoms respond less well effects are often gender-dependent
There are better ways to control
glutamatergic plasticity
6/226/22
Theory-based approach
Developing a behavioral model
Detailed maping of neuronal activation patterns
Detailed analysis of activated neurons
(e.g. chemotype identification,network analysis, etc.)
Unbiased approach(applied earlier in identifying
the neural backgroundof violent forms of aggression
and proposing NK1 blockers for treatment)
Describing the neuralcontrol of the behavior
in question - new treatment approaches
Testing the theory by behavioral pharmacology
If the theory is right:new treatment approaches
Theory driven approach
Detailed functional maping of cortical networks
Theory on the role of particular neurons
Department of functional and
cellular neuroanatomy(T.F. Freund)
Department of BehavioralNeurobiology
(J. Haller)
Unbiased approach
7/227/22
CB1cannabinoidreceptorok
Calretinincell
CCKbasket
cellParvalbuminbasket cell
GABAA receptorokα2 alegységgel
GABAA receptorsmainly with α1 subunits
GABAA receptorsmainly with α2 subunits
M2 muscarinicreceptors
serotonergic
innervation
5-HT3receptors
CCK - Breceptors
The theory: a neuron made for anxiety
CB1cannabinoid
receptors
Nicotinic receptorswith α4 and α7
subunits
Specifically involved in anxiety
8/228/22
CB1cannabinoidreceptorok
Calretinincell
CCKbasket
cellParvalbuminbasket cell
GABAA receptorokα2 alegységgel
GABAA receptorsmainly with α1 subunits
GABAA receptorsmainly with α2 subunits
M2 muscarinicreceptors
serotonergic
innervation
5-HT3receptors
CCK - Breceptors
Cannabinoid signaling and anxiety
CB1cannabinoid
receptors
Nicotinic receptorswith α4 and α7
subunits
Specifically involved in anxiety
Axon terminal Postsynaptic membrane
GABA
CB1 receptors
GABA
Endocannabinoids
9/229/22
0
10
20
30
40
Ope
n a
rm e
xplo
ratio
n (
% ti
me
)
No changes in locomotion
Testing the hypothesis and ...strange findings with endogenous cannabinoids
WIN-55,212
WT CB1-KO
*
*
AM-251
WT CB1-KO
**
AM+WIN
WT CB1-KO
*
Saline
WT CB1-KO
*
0
10
20
30
40
Ope
n a
rm e
xplo
ratio
n (
% ti
me
)
CD1 mice
Sal Anaminutes
Saline
1 2 3 4 5minutes
Andamide
1 2 3 4 5 Sal Ana
*
mice calledby phone
minutes
Saline
1 2 3 4 5minutes
Andamide
1 2 3 4 5
Subtle changes in endogenous cannabinoid signalling change the response of mice to environmental stimuli
Coward
Brave
10/2210/22
re-experiencing (e.g. exaggerated responses to cues)
avoiding cue-associated cues
hyperarousal (e.g. hypervigilence)
CB1cannabinoid
receptors
Trauma(life-threatening stress)
PTSD and the response to environmental stimuli
Trauma-related deficits are glutamate-dependent
Glutamate receptorsCB1/x receptors
Cannabinoids (i) control the response to stimuli (neurobehavioral evidence)(ii) control glutamatergic discharges (neurophysiological evidence)
Cannabinoids must have a role in PTSD
11/2211/22
0
20
40
60
80
100
1 2 3 4 5 6 7 8 9 10Time (min)
Exp
lora
tion
(%tim
e)
0
20
40
60
80
100
1 2 3 4 5 6 7 8 9 10Time (min)
Res
ting
(%tim
e)
** *
*
0
20
40
60
80
100
1 2 3 4 5 6 7 8 9 10Time (min)
Fre
ezin
g (%
time)
* *o
* **
*
The conditioned fear test as model of PTSD
24 hours
Model of post-traumatic stress disorder
Symptom modelledCluster "B" re-experiencing the trauma by symptom 4 intense psychological distress in response to trauma-associated cues
12/2212/22
0
10
20
30
40
1 2 3 4 5
control
shock
shock AM251 1mg/kg
shock AM251 3mg/kg
fre
ezin
g (
%tim
e)
time (min)
WT-shockWT-control
KO-shockKO-control
fre
ezin
g (
%tim
e)
0
10
20
30
40
1 2 3 4 5time (min)
* **
*
*
#0
20406080
100
control
shock
shock WIN55,212 1mg/kg
fre
ezin
g (
%tim
e)
1 2 3 4 5time (min)
shock WIN55,212 3mg/kg
**
* *
##
# # #
#
0204060
80100
1 2 3 4 5
fre
ezin
g (
%tim
e)
shock
shock WIN03
shock WIN3
shock WIN03AM1
shock WIN3AM1
time (min)
## # #
#
CB1 gene disruptionabolishes conditioned freezing
CB1 blockade slightlydecreases conditioned freezing
CB1 activationincreases conditioned freezing
The antagonist blocksthe effects of the agonist
The interaction between cannabinoid signaling and conditioned fear
0
100
200
300
400
coun
ts
Open-field(mice shocked 24h earlier)
WIN0 WIN03 WIN1 WIN3
AM-251 hadno effect on locomotion
up to 55 mg/kg(literature)
13/2213/22
Cannabinoids and contextual and cue-induced conditioned fear
Contextualconditioned fear
(hippocampus-specific)
Cue-inducedconditioned fear
(amygdala-specific)
Cannabinoids promote theexpression of fear
Cannabinoids promote theextinction of fear
(no effect on expression)
Specificinvolvementin trauma?
Unpecificeffect
(consequence ofmemory-releted
effects)?
Hal
ler
et a
l., 2
006
Marsicano et al., 2002
Different distribution ofCB1 receptors in,
and/or different rolesof cannabinoids in
controlling the,amygdala and hippocampus?
Involvement of other corticalstructures (e.g prefrontal cortex)
in the differential effects?
Cannabinoids promote behavioral dysfunctions induced by traumatic experiencethis appears to be valid for behaviors largely controlled by the hippocampus
Cannabinoids promote the extinction of aversive memoriesthis is apparent in behaviors largely controlled by the amygdala
The involvement of cannabinoids in trauma-related behavioral dysfunctions suggests that cannabinoid signaling is involved in post-traumatic stress disorder
14/2214/22
Interactions between 5-HT3 and CB1 receptors in conditioned fear
5-HT3receptors
CB1cannabinoid
receptors
15/2215/22
The effects of the 5-HT3 agonist mCPBG on anxiety
0
10
20
30
40
Closedentries
% timeopen arms
% openentries
Sal
1 mg/kg
3 mg/kg
10 mg/kg
Elevated plus-maze
Conditioned fear
0
5
10
15
20
25
30
35
1 2 3 4 5 6 7 8 9 10
min
free
zin
g (
% t
ime)
vehicle, no shock
shock, vehicle
shock, 3 mg/kg mCPBG
shock, 10 mg/kg mCPBG
The 5-HT3 agonist does not affect plus-maze anxiety (natural fear)
The same agonist prolongsthe conditioned fear responsewithout affecting amplitude
## # #
#
16/2216/22
Concurrent 5-HT3 agonism and CB1 blockade abolishes conditioned fear
Conditioned fear
0
5
10
15
20
25
30
35
1 2 3 4 5 6 7 8 9 10
min
Fre
ezin
g (
%ti
me) vehicle, no shock
shock, vehicle
shock, mCPBG 3mg/kg
shock, mCPBG 3 mg/kg + AM-251 0.3 mg/kg
shock, mCPBG 3 mg/kg + AM-251 1 mg/kg
0
10
20
30
40
1 2 3 4 5
control
shock
shock AM251 1mg/kg
shock AM251 3mg/kg
fre
ezin
g (
%tim
e)
time (min)
*
*
#
For comparison: the effects of AM-251 ConclusionThere is an unexpectedly strong interaction between mechanisms mediated by 5-HT3 and CB1 receptors, that may be involved inther control of behavioral dysfunctons induced by trauma exposure
Cannabinoids -alone or in combination- are potentially important in the treatment of
trauma-induced behavioral deficits
CCKinterneuron
GABACCK
anxiolytic
anxiogenic
One problem: was the model good enoughto draw this conclusion?
17/2217/22
Despair
Helplessness
Mania
Glucocorticoidexcess
Behavioralsuppression
Etc.
Learnedhelplessness
Forcedswimming
Chronicmild stress
Bulbectomy/open field
Chronicrestraint
Forcedsubmission
Etc.
Anhedonia
The usual way of modeling psychiatric disorders
(1) Tearing symptoms apart (depression is just an example)
(2) Building models for each symptom
(3) Bringing the bits together - theoretical perfection
(3) What often happens in practice
A better solution: modeling the disorder.Is this possible?
This may be feasible in PTSDwhere all symptoms have one single cause:
the trauma
18/2218/22
A symptom by symtom analysis of a PTSD model
"New pharmacological approaches need new behavioral methods"
Traumas employed in the laboratory Electric shocks of various strength, durations, aggravated or not with cue reminders Cat exposure Suffocation stress Restraint + forced swim + halothane or etherBehavioreal deficits investigated Limited number (usually one), often after a limited time interval
Can a complex disorder be modelled simply?
Question asked: can we create a rat in which PTSD can be DIAGNOSED?
19/2219/22
DSM-IV criteria for PTSDTriggering factor (Cluster A): traumatic event (1) life threatening (2) helplessReexperiencing the trauma (Cluster B) (1) distressing recollections (2) distressing dreams (3) reliving the experience by illusions, hallucinations, and dissociative flashbacks (4) psychological distress when faced with trauma-related cues (5) psychological distress when faced with trauma-related cuesAvoidance and numbing (Cluster C) (1) avoiding trauma-related thoughts, feelings, or conversations (2) avoiding trauma-related activities, places, or people (3) inability to recall an important aspect of the trauma (4) diminished interest in significant activities (5) detachment from others (6) restricted range of affect (7) sense of a foreshortened futureHyperarousal (Cluster D) (1) sleep problems (2) irritability (3) difficulty concentrating (4) hypervigilance (5) exaggerated startle response Duration is more than 1 month (Cluster E)
Number of symptoms "required" within a cluster2
2
3
2
1
0
20
40
60
80
100
**
*
*
Objectmanipulation
Objectburying
% ti
me unshocked, object 1
unshocked object 2
shocked (3 mA) object 1
shocked (3 mA) object 2
300
340
380
420
460
eD mD lD eL mL lL Average
Hea
rt r
ate
eD mD lD eL mL lL Average
1 day before shocks 25 days after shocks
eD= early dark phasemD = mid dark phaselD= late dark phaseeL= early light phasemL = mid light phaselL= late light phase Unshocked control Rats shocked with 3 mA currents
0
20
40
60
80
100
% ti
me
in o
ppon
ent's
cha
mbe
r
unshocked0.8 mA shocks3 mA shocks*
*#
*#
*
1 day after shock
28 days after shock
12Days after shock
0
100
200
300
400 Open field
6 24
Lin
e cr
oss
ing
s (e
xplo
ratio
n) control
3mA 12 Elevated plus-maze1086420C
lose
ed
arm
en
trie
s
* **
**
*
12Days after shock6 24
0
40
80
120
-5 T 5 10 20 30 Average
**
Heart rate changes compared to baseline
minutes
unshocked0.8 mA shocks3 mA shocks
Freezing Escape jumps
**
*
28 days after shock
Freezing Escape jumps
0
20
40
60
80
100
*
*
*Dur
atio
n (%
time)
1 day after shock
unshocked0.8 mA shocks3 mA shocks
Group Freezing(seconds)
Escape jumps(counts)
Vocalizations
duration (sec) latency (sec)
Unshocked control 0.0±0.0 0.0±0.0 0.0±0.0 300±0†
0.8 mA shocks 24.6±6.6* 1.0±1.0 2.5±0.6 76.7±12.8*
3 mA shocks 44.3±15.1* 14.4±6.2*# 8.3±0.3*# 6.8±4.6*#
Deficits seen in rats receiving 10, 1 sec long, 0.8 or 3 mA shocks over 5 min
12days after shock
The duration of the deficits is at least 4 weeksAlso consider the life-span of rats
0
40
80
120
-5 T 5 10 20 30 Average
*
++
++ +
SOC AGO0
5
10
15
20
25
% ti
me
Rez. intr.
*
20/2220/22
DSM-IV criteria for PTSDTriggering factor (Cluster A): traumatic event (1) life threatening (2) helplessReexperiencing the trauma (Cluster B) (1) distressing recollections (2) distressing dreams (3) reliving the experience by illusions, hallucinations, and dissociative flashbacks (4) psychological distress when faced with trauma-related cues (5) psychological distress when faced with trauma-related cuesAvoidance and numbing (Cluster C) (1) avoiding trauma-related thoughts, feelings, or conversations (2) avoiding trauma-related activities, places, or people (3) inability to recall an important aspect of the trauma (4) diminished interest in significant activities (5) detachment from others (6) restricted range of affect (7) sense of a foreshortened futureHyperarousal (Cluster D) (1) sleep problems (2) irritability (3) difficulty concentrating (4) hypervigilance (5) exaggerated startle response Duration is more than 1 month (Cluster E)
Number of symptoms "required" within a cluster2
2
3
2
1
Can the disorder be modelled as a whole?
Rats shocked with 3 mA currents reach a state that can be considered an animal variant of PTSD
21/2221/22
The next step
Sound theory supported by experimental evidence
Good modelGO!
22/2222/22