Autonomic pharmacology I Flashcards
which organs receive only sympathetic innervation?
- hair follicles
- thermoregulatory sweat glands
- liver
- adrenal glands
- kidney
all preganglionic fibers secrete which NT?
Ach
which enzyme is responsible for brining choline into the nerve terminal?
CHT
which drug blocks entry of choline into the nerve terminal?
hemicholiniums
which enzyme is responsible for brining Ach into the vesicle?
VAT
which enzyme is responsible for forming Ach from AcCoA and choline?
ChAT
which drug blocks entry of Ach into the vesicle?
vesamicol
which enzymes are responsible for fusion of vesicle to the nerve terminal membrane?
VAMPs
what is the function of neostigmine?
Anticholinesterase - increases Ach in synapse and thus PNS function
what is the function of tubocurarine?
neuromuscular blocking agent - cholinoceptor antagonist
which receptor is found on the dilator (radial) muscle of the iris?
a1
which receptor is found on the constrictor (sphincter) muscle of the iris?
M3
which receptors are found on the ciliary muscle?
M3, B2
which receptors are found on the ciliary body epithelium?
a2, B1, B2
what is the result of M3 receptor activation in the eye?
- constriction of sphincter pupillae muscle
- contraction of ciliary muscle (relaxation of lens)
- opening of Canal of Schlemm
what is the result of muscarinic antagonism in the eye?
- mydriasis (no M3 activity)
2. paralysis of accommodation - cycloplegia (no M3 activity)
what is the primary receptor in the heart?
M2
what is the mechanism of M2 activation in the heart?
- alpha subunit of Gi/o inhibits adenylyl cyclase
- decrease in cAMP
- decrease in PKA
- overall inhibitory
what is the effect of M2 receptor activation on the SA node?
decreased HR - negative chronotropy
what is the effect of M2 receptor activation on the AV node?
decreased conduction velocity
what is the effect of M2 receptor activation on the atrial muscle?
decreased atrial contraction
what is the effect of M2 receptor activation on ventricular muscle?
decreased ventricular contraction (weak effect)
what is the effect of M3 receptor activation on the bronchi and bronchioles?
contraction - bronchospasm
what is the effect of M3 receptor activation on the bronchiolar submucosal glands?
secretion, narrowed lumen
are M3 receptor activators or inhibitors better for treating an asthma attack?
inhibitor
what is the effect of M3 receptor activation on the stomach?
increased motility and cramps
what is the effect of M1, M3 receptor activation on GI glands?
secretion
what is the effect of M3 receptor activation on the intestines?
contraction - diarrhea, involuntary defecation
why is it that both M1 and M3 receptors play a role in controlling gastric acid secretion?
- Ach via vagus directly activates parietal cells (M3) - increased proton production
- Ach via vagus activates M1 receptors on ECL cells - histamine production (which later stimulates H2 receptors on parietal cells)
what is the effect of M3 receptor activation on the bladder?
- contraction of detrusor
- relax trigone / sphincter
- voiding / incontinence
what is the effect of M3 receptor activation on normal blood vessels?
Ach binds to M3 receptors on endothelial cells leading to calcium influx and Gq activation - eventual production of NO and vasodilation
what is the effect of M3 receptor activation on blood vessels with damaged endothelial cells?
vasoconstriction - Ach activates M3 receptors directly on smooth muscle (unopposed by NO from endothelial action)
