effects of adrenergic receptor agonists / antagonists on...
TRANSCRIPT
Department of PharmacologyYun-Bi Lu, San-Hua Fang, Wei-Wei Hu
[email protected]@zju.edu.cn
Effects of adrenergic receptor Effects of adrenergic receptor agonists / antagonists on agonists / antagonists on arterial blood pressure in rabbitarterial blood pressure in rabbit
[Objectives]
To observe the pharmacological effects of adrenergic agonists on regulation of arterial blood pressure in rabbit.
To demonstrate and analyze the underlying mechanisms of adrenergic agonists actions by using adrenergic antagonists.
[Principle]
vasodilation(skeletal muscle vasculature)
enhancement of heart rate, contractility and conduction velocity
inhibition of norepinephrinerelease
Vasoconstriction(arterioles, veins)
Effects
Postsynaptic,blood vessels
Postsynaptic, heart
PresynapticPostsynaptic, Smooth muscular cells of blood vessels
Distribution
β2β1α2α1Receptor type
[Principle]
antagonistβ1, β2propranololantagonistα1, α2phentolamine
agonistβ1, β2Isoprenaline(isoproterenol)
agonistα1, α2 (β1)Noradrenaline(norepinephrine)
agonistα1, α2, β1, β2Adrenaline(epinephrine)
EffectReceptor specificityDrug
Adrenoceptors
Effects of Effects of catecholaminescatecholamines((therapeutic dosestherapeutic doses))
Predominant Effects:Predominant Effects:NE :NE : αα effects effects & & veryvery weakweak ββ11 effectseffectsEPI :EPI : αα effects (higher concentrations)effects (higher concentrations) ββ effects (lower concentrations) effects (lower concentrations) ISO: ISO: ββ11 and and ββ 2 2 effectseffects
Isoprenaline( )
Noradrenaline( )
Adrenaline ( )
Phentolamine( )
Isoprenaline( )
Noradrenaline( )
Adrenaline ( )
Control
Heart rate (bpm)
Pulse pressure (mmHg)
SP/DP[Systolic blood
pressure /Diastolic blood pressure](mmHg)
Treatment 2 (dose)
Treatment 1 (dose)
control control control
control
The underlying action mechanism of adrenaline
ββ1:1: contractility contractility ↑↑HR HR ↑↑
αα11::vasoconstriction vasoconstriction (skin, mucous, viscera), (skin, mucous, viscera),
ββ22::vasodilatation of skeletal vasodilatation of skeletal muscles and coronary vesselsmuscles and coronary vessels
cardiac output cardiac output ↑↑Peripheral resistancePeripheral resistance--↓↓
Systolic BP Systolic BP ↑↑Diastolic BP Diastolic BP ↓↓(slightly)(slightly)Pulse pressurePulse pressure ↑↑
The underlying action mechanism of noradrenaline
αα11::vasoconstriction (skin, renal, brain, vasoconstriction (skin, renal, brain, hepatic, mesenteric, hepatic, mesenteric, etcetc.).)
αα22::inhibiting NE releaseinhibiting NE releaseββ1: 1: weak directly cardiac stimulatesweak directly cardiac stimulates
cardiac output cardiac output ↑↑ (slightly) (slightly) Peripheral resistancePeripheral resistance ↑↑
Systolic BP Systolic BP ↑↑Diastolic BP Diastolic BP --pulse pressure pulse pressure ↑↑
cardiaccardiac inhibition inhibition viaviareflexreflex ((baroreceptorbaroreceptor))
Heart rate Heart rate ↓↓
The underlying action mechanism of isoproterenol
ββ1:1: contractility contractility ↑↑ HR HR ↑↑ββ2 :2 : dilatation of skeletal muscles dilatation of skeletal muscles and coronary vesselsand coronary vessels
cardiac output cardiac output ↑↑Peripheral resistancePeripheral resistance ↓↓
Systolic BP Systolic BP ↑↑Diastolic BP Diastolic BP ↓↓pulse pressure pulse pressure ↓↓
BP
αα antagonistantagonistX drugX drug X drugX drug
Experiment Report
SubjectObjectivesMaterials and methods:ResultsDiscussionConclusion