MMT: Pharmacology of Autonomic Drugs

Question 1

what are the two main classes of receptors?

Answer 1

cholinergic and adrenergic

Question 2

what are the two subdivisions of cholinergic receptors? what are their methods of action?

Answer 2

Muscarinic: GPCRs

Nicotinic: ion channels that are permeable to cations, particularly Na.

Question 3

Which muscarinic receptors are associated with Gq? What is the significance of this?

Answer 3

M1, M3, M5. Since they’re associated with Gq, they all stimulate the release of calcium and thus the contraction of smooth muscle

Question 4

Which muscarinic receptors are associated with Gi? What is the significance of this?

Answer 4

M2 and M4. They’re associated with lowering cAMP and increasing potassium efflux, which leads to hyperpolarization. They’re also associated with lowered PKA, which decreases Ca channel activity. This slows AP conduction

Question 5

what are the subdivisions of adrenergic receptors?

Answer 5

alpha and beta

Question 6

what is the method of action for adrenergic receptors?

Answer 6

GPCR

Question 7

Describe alpha1-adrenergic receptors: general effect, what they’re coupled to, their downstream effect, and what they stimulate

Answer 7

They’re typically excitatory and regulate the SNS. They’re coupled to Gq and increase calcium release via IP3. they stimulate the constriction of smooth muscle.

Question 8

Describe alpha2-adrenergic receptors

Answer 8

They’re typically inhibitory and reduce sympathetic outflow. They’re coupled to Gi. They’re present on presynaptic nerve terminals and prevent norepinephrine release via a negative-feedback mechanisms. If there is too much NE in the synaptic cleft, it acts of alpha2 receptors and prevent further NE release

Question 9

Describe beta1-adrenergic receptors: general effect, their downstream effector, what they stimulate

Answer 9

They’re excitatory and regulate the SNS. They are coupled to Gs, and stimulate cAMP and contraction of heart muscle

Question 10

describe beta2-adrenergic receptors: general effect, what they’re coupled to, their downstream effect, and what they stimulate

Answer 10

They’re inhibitory and regulate the SNS. they are coupled to Gs, and stimulate cAMP and relaxation of smooth muscle.

Question 11

Describe how increased cAMP impacts cardiac and smooth muscle

Answer 11

Increases cardiac muscle contraction, but relaxes smooth muscle

Question 12

SA node: sympathetic receptor and nervous system response vs parasympathetic receptor and nervous system response

Answer 12

Sympathetic b1 receptor, increased heart rate
Parasympathetic m2 receptor, decreased heart rate

Question 13

AV node: sympathetic receptor and nervous system response vs parasympathetic receptor and nervous system response

Answer 13

Sympathetic b1 receptor increases conduction, parasympathetic m2 receptor decreases conduction

Question 14

Atria: sympathetic receptor and nervous system response vs parasympathetic receptor and nervous system response

Answer 14

Sympathetic b1 receptor increases contractility, parasympathetic m2 receptor decreases contractility

Question 15

ventricles: sympathetic receptor and nervous system response vs parasympathetic receptor and nervous system response

Answer 15

sympathetic b1 receptor increases contractility, and parasympathetic m receptor decreases contractility; actions of PSNS are almost negligible.

Question 16

Blood vessels in skeletal muscle: impact of sympathetic and parasympathetic receptors

Answer 16

Sympathetic a1 receptors increase vasoconstriction, while sympathetic b2 receptors decrease vasoconstriction. m receptors are present, but are not innervated by the parasympathetic nervous system. Stimulating them decreases vasoconstriction

Question 17

Blood vessels in skin and mucosa: impact of sympathetic and parasympathetic receptors

Answer 17

Sympathetic a1 receptors increase vasoconstriction

Question 18

Bronchi smooth muscle: sympathetic receptor and nervous system response vs parasympathetic receptor and nervous system response

Answer 18

Sympathetic b2 receptors relax smooth muscle, parasympathetic m receptors increase contraction of smooth muscle

Question 19

what receptors are associated with increased salivary and sweat gland secretion?

Answer 19

salivary: sympathetic a1 receptors and parasympathetic muscarinic receptors

sweat: sympathetic muscarinic receptors

Question 20

Where are beta2 sympathetic receptors primarily found?

Answer 20

Blood vessels feeding skeletal muscle

Question 21

Urinary bladder detrusor: impact of sympathetic and parasympathetic receptors

Answer 21

Sympathetic b2 and b3 receptors decrease bladder contraction, parasympathetic m receptors increase contraction

Question 22

Urinary bladder trigone and sphincter: impact of sympathetic and parasympathetic receptors

Answer 22

Sympathetic a1 receptors contract the sphincter, parasympathetic m receptors relax the sphincter

Question 23

Describe the role of sympathetic and parasympathetic nervous systems and their receptors in contracting and dilating the eye

Answer 23

Parasympathetic m3 receptors in the iris sphincter muscle contract the pupil, while sympathetic alpha1-AR receptors in the iris radial muscle increase pupil size

Question 24

What is the ciliary body?

Answer 24

Composed of smooth muscle and epithelial cells that create aqueous humor to nourish the eye. It comes through the pupil and drains through the iris/cornea

Question 25

Describe how the parasympathetic nervous system impacts the lenses of the eye

Answer 25

When m3 receptors are activated, the ciliary body is constricted which will impact the curvature of the lense, making it curve up. This lets us see things closer up vs farther away

Question 26

Where does the sympathetic nervous system use muscarinic receptors, and for what purpose?

Answer 26

In the sweat glands to increase secretion

Question 27

Describe the effect of parasympathetic receptors on salivary glands

Answer 27

Muscarinic receptors increase secretion

Question 28

What receptors are present in autonomic ganglia? What is the impact?

Answer 28

Nicotinic; increased NT release for both sympathetic and parasympathetic

Question 29

What receptors are present in adrenal medulla? What is the impact?

Answer 29

Nicotinic; increased sympathetic neurotransmitter release

Question 30

Where are the main places we find baroreceptors to detect stretch?

Answer 30

Aortic arch and carotid sinus

Question 31

Describe the effects of raised/lowered mean arterial pressure (MAP) on the SNS and PSNS

Answer 31

Raised MAP: increased PSNS, decreased SNS, lowered heart rate

Lowered MAP: increased SNS, lowered PSNS, raised heart rate

Question 32

what is mydraisis? miosis?

Answer 32

mydraisis: enlarged pupil; a1 receptor
miosis: smaller pupil; M3 receptor

Question 33

where does the sympthetic system have dominant tone?

Answer 33

arterioles, veins, sweat glands, and splits genital tract with parasympathetic. everything else has dominant parasympathetic tone!