1.3 Adrenergic Receptors

Jackson

the autonomic nervous system is broken into which two categories

parasympathetic and sympathetic

what type of receptors are in the parasympathetic nervous system

cholinergic

what type of receptors are in the sympathetic nervous system

adrenergic

what are the adrenergic receptor substypes

alpha and beta

what neurotransmitters bind to adrenergic receptors

catecholamine (NE and EPI)

what type of neurotransmitters bind to cholinergic receptors

ACh

adrenergic agonists/agents are also called

sympathomimetics

adrenergic agonists or sympathomimetics function

to mimic the response that the usual neurotransmitter would elicit, they cause the normal response that the receptor leads to

catecholamines are able to produce a ____ response

sympathomimetic (agonistic)

what are the endogenous catecholamines

EPI, NE, and dopamine

what are the synthetic catecholamines

isoproterenol, dobutamine, and phenylephrine

when NE is IV infused, what happens to:
pulse rate, blood pressure, and peripheral resistance

decrease, increase, increase

when EPI or ISO are IV infused, what happens to:
pulse rate, blood pressure, and peripheral resistance

increase, decrease, decrease

receptor affinity

strength of attraction to a receptor, like preference

receptor selectivity

drug/agent only binds to that specific receptor

NE has _____ for alpha receptors

affinity

NE has affinity for ____ receptors

alpha

EPI is ____ for adrenergic receptors

non-selective

EPI has ____ for B receptors

affinity

EPI has affinity for ____ receptors

Beta

ISO has ____ for Beta receptors

selectivity

True or false:

ISO does not have preference/affinity between the beta receptors

True

alpha 1 receptors are GPCR’d with which G protein

Gq

Gq is bound to which adrenergic receptor

alpha 1

explain the pathway for alpha-1 receptor agonist effects

1. alpha 1 receptor is activated via catecholamine or agonist

2. activates phospholipase C

3. creates IP3

4. opens Ca channels increases Ca amount

5. Ca binds to calmodulin protein

6. activates myosin kinase

7. phosphorylates myosin

8. vasoconstriction

B2 receptors are coupled with which G protein

Gs

Gs is coupled with which adrenergic receptor

B2

explain the pathway for alpha-2 receptor catecholamine/agonist effects

1. activation of B2 receptor

2. activates adenylyl cyclase

3. convertes ATP —> cAMP

4. increases cAMP amount

5. cAMP activates protein kinase A

6. phosphorylates myosin kinase (inactivating)

7. vasodilation (bc myosin is not phosphorylated)

alpha 2 receptors are coupled with which G protien

Gi

Gi is coupled with which adrenergic receptor

alpha 2

explain the pathway for alpha-2 receptor catecholamine/agonist effects

1. inhibits adenylyl cyclase

2. decreases cAMP concentration

3. decreases protein kinase A activity

4. myosin kinase phosphorylates myosin

5. constriction

B1 receptors are coupled with which G protein

Gs

Gs is coupled with which adrenergic receptor

betas

explain the pathway for beta-1 receptor catecholamine/agonist cardiac effects

1. activates adenylyl cyclase

2. converts ATP to cAMP

3. increased cAMP conc

4. activates protein kinase A

5. increases Ca conc

6. increases force and contraction of the heart

explain the pathway for beta receptors catecholamine/agonist metabolic effects

1. activates adenylyl cyclase

2. converts ATP —> cAMP

3. increased cAMP conc

4. lipolysis, gluconeogenesis

5. energy formation

what are the alpha adrenergic receptor subtypes

alpha 1 and alpha 2

where are alpha 1 adrenergic receptors located

postsynaptic effector cells (on cells, muscle, or organs)

where are alpha 2 adrenergic receptors located

on the presynaptic nerve terminals that stimulate the effector cells

which type of alpha receptor controls NT release

alpha 2

dopamine is a type of ____ receptor

adrenergic

what are the subtypes of dopamine receptors

d1 and d2

dopamine receptors are stimulated by

dopamine

when dopamine receptors are stimulated, it leads to…

vasodilation, increased blood flow and decreased blood pressure of certain vessels

which blood vessels are effected by dopaminergic receptors

mesenteric, coronary, renal, and cerebral

how do direct acting sympathomimetics work

they bind directly to the receptor to cause the response that the typical NT’s would

how do indirect acting sympathomimetics work

they cause the release of NT catecholamines from the vesicles in the nerve endings

how do mixed acting sympathomimetics work

they can either directly stimulate the receptor by binding to it or they can cause release of stored catecholamines

where are alpha 1 receptors found in the cardiovascular system

blood vessels

where are alpha 2 receptors found in the cardiovascular system

no where fam

where are beta 1 receptors found in the cardiovascular system

cardiac muscle, AV node, and SA node

where are beta 2 receptors found in the cardiovascular system

blood vessels

what response do alpha 1 receptors on blood vessels in the CV system have

constriction and dilation

what response do beta 2 receptors on blood vessels in the CV system cause…

dilation and constriction

beta 1 receptors on cardiac muscle in the CV system cause…

increased contractility

beta 1 receptors on AV and SA nodes in the CV system cause…

increased heart rate

what adrenergic receptor(s) in the cardiovascular system leads to constriction/dilation of the blood vessels?

alpha 1 and beta 2

what receptors in the cardiovascular system cause increased contractility of the cardiac muscle?

beta 1

what adrenergic receptor(s) in the CV system cause increased heart rate?

beta 1

which adrenergic receptor is found in the muscle of the GI system

beta 2

response of beta 2 receptors on the muscle in the GIT

decreased motility

which adrenergic receptors are found on the sphincters in the GIT

alpha 1

what response do alpha 1 receptors in the sphincters of the GIT cause

constriction

what adrenergic receptor(s) in the GIT cause decreased motility?

beta 2

what adrenergic receptors in the GIT sphincters lead to constriction?

alpha 1

what adrenergic receptor is found in the bladder sphincter

alpha 1

what response does the alpha 1 receptor on the bladder sphincter have

constriction

what adrenergic receptor is found in the penis

alpha 1

what response does the alpha 1 receptor have in the penis

ejaculation

what adrenergic receptor is found in the uterus

alpha 1 and beta 2

what response does alpha 1 receptor have in the uterus

contraction and relaxation

what response does beta 2 receptor have in the uterus

contraction and relaxation

what adrenergic receptors in the bladder sphincter cause constriction?

alpha 1

what adrenergic receptors in the genitourinary system cause ejaculation?

alpha 1

what adrenergic receptor(s) in the genitourinary system cause contraction and relaxation of the uterus

alpha 1 and beta 2

what adrenergic receptor is located in the bronchial muscles

beta 2

what is the response of beta 2 receptors in the bronchial muscles

dilation and relaxation

what adrenergic receptor (s) in the respiratory tract cause dilation/relaxation of the bronchial muscles

beta 2

alpha 1 receptor function

smooth muscle contraction

alpha 2 receptor function

negative FB causes less NE to be released

beta 1 receptor function

cardiovascular effects

beta 2 receptor function

bronchodilation and vasodilation

beta 3 receptor function

actual site for lipolysis

alpha 2 receptors in the CNS can be useful for…

decreasing BP

True or false:

most body tissues have both alpha and beta receptors

true

what receptors does dopamine effect

alpha, beta, and dopaminergic

adrenergic agents interactions

anesthetic agents, tricyclic antidepressants, MAOIs, antihistamines, thyroid preparations, antihypertensives