Autonomic NS 1: Adrenergic receptors Flashcards
Alpha 1 receptor is mainly—–
Post-synaptic
Mechanism of Alpha 1 adrenergic receptor
facilitate Gq protein as second messenger
Actions of Alpha 1 Adrenergic receptors
VC,eyes,hair,stop GIT
- Generealized Vasoconstriction (Skin, mucous membrane,internal abdominal organs, splanchnic BVs)
Contraction of:
* Dilator pupilae –> pupil dilatation (mydrasis)
* Erector Pile (hair erectors)
* All sphincters of GIT & urinary tract
Relaxation of:
* wall of GIT
+
Facilitates neuromuscular transmission
Alpha 2 receptor is present in—-
- Presynaptic
- postsynaptic
- CNS
Mechanism of Alpha 2 receptor
facilitate Gi protein as second messenger
Action of Alpha 2 receptor
- Decreases Sympathetic flow from CNS
- Relaxation of GIT wall (decrease peristalsis)
- Decrease Insulin secretion
- Decrease lipolysis
- Decrease Renin
Both Alpha1 & Alpha2 receptors cause
- Relaxation of wall of GIT
- Viscid salivary secretion
- Facilitate neuromuscular transmission
Site of Beta1 Adrenergic receptors
Cardiac muscles (mainly)
Mechanism of Beta1 adrenergic receptors
facilitate Gs protein as second messenger
Action of Beta1 adrenergic receptors
- Increase all cardiac properites (Contractility, excitability, conductivity, Heart rate)
3aks el Alpha 2:
* stimulate lipolysis (with B3)
* Increase Renin
Increase Aqueous Humour of the eye (with B2)
Relaxation of GIT wall
site of Beta 2 adrenergic receptors
mainly in smooth muscles
Mechnism of Beta 2 adrenergic receptors
increase cAMP
Action of Beta 2 Adrenrgic receptors
EL HOROOB
- VD to skeletal & Coronary Blood vessels
- Bronchodilatation
Increase energy, plasma glucose & glucose utilisation:
* increase insulin secretion
* Increase Glycogenolysis
* Increase Lipolysis
Relaxation of:
* GIT wall
* Urinary bladder wall
* Uterus wall
-Muscle tremors
-Increase Intracellular potassium uptake/ decerease extracellular potassium/hypokalemia: to facilitate more muscular contractions
-Increase Aqueous Humour
Mechanism & action of Beta 3 Adrenergic receptors
Increase cAMP:
* Increase lipolysis —> increase FFA circulating
Selective Beta 3 Agonist
Octopamine
function of Adrenergic presynaptic receptors
they are found in CNS and Facilitate Negative feedback (autoreceptors) of NorAdrenaline release
stimulation of presynaptic Alpha 2 Adrenergic receptor leads to
Decrease NA release
stimulation of presynaptic Beta Adrenergic receptor leads to
Increase NA release
Adrenergic receptors facilitating generalied VC
Alpha 1
Adrenergic receptor Facilitating Relaxation of GIT wall
(all except Beta3)
* Alpha 1
* Alpha 2
* Beta 1
* Beta 2
Which Adenergic receptor facilitates Mydrasis (pupil dilatation)
Alpha 1
Which Adenergic receptor facilitates Hair erection
Alpha 1
Which Adenergic receptor facilitates Neuromuscular transmission
both Alpha 1 & Alpha 2
Which Adenergic receptor results in Viscid Salivary secretion
both Alpha 1 & Alpha 2
Which Adenergic receptor Decrease Sympathetic Flow from CNS
Alpha 2
Which Adenergic receptor decreases insulin secretion
Alpha 2
Which Adenergic receptor decrease Renin
Alpha 2
Which Adenergic receptor decreases Lipolysis
Alpha 2
Which Adenergic receptor faciliatates contraction of all GIT & urinary Sphincters
Alpha 1
Which Adenergic receptor increases all cardiac properties
Beta 1
Which Adenergic receptor increases Lipolysis
all Beta
* Beta 1
* Beta 2
* Beta 3
Which Adenergic receptor increases renin
Beta 1
Which Adenergic receptor increases Aqueous humour formation
Beta 1 & Beta 2
Which Adenergic receptor facilitates VD of Coronary & skeletal BVs
Beta 2
Which Adenergic receptor facilitates bronchodilatation
Beta 2
Which Adenergic receptor increases intracellular uptake of potassium
Beta 2 (to increase contraction)
Which Adenergic receptor causes relaxation of wall of uterus
Beta 2
Which Adenergic receptor causes relaxation of urinary bladder
Beta 2
Which adrenergic receptor increases glycogenolysis & insulin secretion
Beta 2
Which Adenergic receptor causes muscle tremors
Beta 2
