Patient: Alpha Adrenoceptors Flashcards
Alpha Adrenoceptors
Two branches of the autonomic nervous system and what kind of receptors lie there
Sympathetic- noradrenaline
Parasympathetic - acetylcholine
Alpha Adrenoceptors
Adrenal Medulla
Adrenaline (epinephrine)
which is under he sympathetic nervous system
Alpha Adrenoceptors
Adenoreceptors modulate the “fight or flight” response. Name 9 examples of tissues where they can act
- Blood vessels
- heart
- Lungs
- GI tract
- Salivary glands
- bladder
- genitalia
- eyes
- sweat glands
Alpha Adrenoceptors
Name 3 adrenoreceptors
Alpha1, alpha2
beta1, beta2, beta3
Alpha Adrenoceptors
Functional responses of alpha1 adrenoceptors
- GPCR - Galphaq
- Increases Ca2+ concentration via..activating phospholipase C–>IP3
- vasoconstriction (increase BP)
- Contraction of visceral smooth muscle e.g. bladder sphincter, uterus, iris radial muscle, seminal tract, pilomotor muscles
- Relax GI tract
Alpha Adrenoceptors
Define seminal tract
Secrete semen
Alpha Adrenoceptors
Define pilomotor muscles
Contraction of the smooth muscle of the skin caused by mild application of a tactile stimulus or by local cooling and resulting in goose bumps
Alpha Adrenoceptors
Functional response of alpha2 adrenoceptors
- Decrease in noradrenaline and acetylcholine transmitter release
- Decrease in insulin release
- GPCR Galphai activates adenylyl cyclase
- causes reduction in cAMP
- Decrease in Protein kinase A
Alpha Adrenoceptors
Functional response of beta1 adrenoceptors in the
Heart
Kidney
Adipocytes
Binds GPCR Galphas activates adenylyl cyclase increase in cAMP increase in protein kinase A hence: Heart - Increase heart rate (SA node) and increase force of contraction Kidney - release of renin Adipocytes - activates lipolysis
Alpha Adrenoceptors
Describe what renin is
Hormone that affects:
- Na reabsorption
- angiotensin 2
- vasoconstrictor
Alpha Adrenoceptors
Functional response of beta2 adrenoceptors
GPCR Galpha2s activates adenylyl cyclase increase in cAMP increase PKA
Bronchodilation-vasodilation (sk muscle) very little change in BP
- relax visceral smooth muscle
- bladder
- detrusor muscle
- uterus
- ciliary muscle
- seminal tact
- muscle tremor
- glcogenolysis
Alpha Adrenoceptors
Define detrusor muscle
Muscle that forms layer of wall in the bladder
Alpha Adrenoceptors
Define ciliary muscle
muscle in the eye
forms part of the ciliary body
Alpha Adrenoceptors
Name an alpha1 agonist
Phenylephrine
Alpha Adrenoceptors
Name an alpha2 agonist
Clonidine
Alpha Adrenoceptors
Name a beta1 agonist
Dobutamine