Autonomic Pharmacology Flashcards
location of baroreceptors (3)
and
location of central autonomic centers
- walls of carotid sinus
- aortic arch
- heart wall
- hypothalamus
- limib system
- medulla oblongata
Somatic system: origin, neurotransmitter, receptor and location
various levels of spinal cord, ACh, nicotinic receptors (Nm), skeletal striated muscle
Autonomic system- Parasympathetic: origin, neurotransmitter, receptor and location
cranial and spinal, Ach, nicotinic receptors in ganglion ;;;; Ach, muscarinig receptors in smooth muscle, cardiac tissue, and secretory glands
Autonomic system - Sympathetic: origin, neurotransmitter, receptor and location
see figure
Muscarinic M2 and M4 receptors
(what are these antagonists of?)
Gi –> inhibit adenylyl cyclase and cAMP signaling
(antagonists of agents like beta receptors that strictly work through activating adenylyl cyclase)
Muscarinic M1, M3, and M5 receptors
signal through Gq –> activate phospholipase C and IP3-DAG signaling —> Calcium binds calmodulin –> activates myosin light chain kinase –> phosphorylation of myosin globular heads, allowing interaction with actin –> **smooth muscle contraction **
How are nicotinic receptors different that muscarinic?
- ionotropic (muscarinic are metabotropic/secondary signaling)
- receptor has instrinsic chanel activity within it
- agonist/ligand binds to receptor, opens channel and get ion passing through
- much faster, since channel is part of the receptor itself (muscarinig have to go through signalling through other proteins)
*
Adrenergic receptors
a type of muscarinic GPCR
2 classes: alpha and beta
NE is released and interacts with receptors
Glaucoma
defect/deficit in outflow of the aqeuous humor fluid. It is constantly being made and drained through the trabecula network. If this drainage gets messed up, you have an elevated intraocular pressure and can destroy the optic nerve.
List the 5 drugs used for glaucoma
- cholinomimetics (cholinergic agonists)
- alpha agonists (non-selective or alpha2-selective
- beta blockers
- carbonic anyhdrase inhibitors
- prostaglandins
For each drug used for glaucoma, describe the effect:
cholinomimetics
ciliary muscle contraction (lens round for close vision), opening of trabecular meshwork, increased outflow
For each drug used for glaucoma, describe the effect: alpha agonists
increased outflow and decreased aqeuous production
For each drug used for glaucoma, describe the effect: beta blockers
decreased aqeuous production
For each drug used for glaucoma, describe the effect: Carbonic anhydrase inhibitors
decreased aqueous production
For each drug used for glaucoma, describe the effect: Prostaglandins
increased outflow
Cholinoceptor agonists
indirectly-acting cholinoceptor agonists
- mimic actions of ACh
- vary in chemical structure and selectivity
- indirectty acting: cholinesterase inhibitors: inhibit the hydrolysis of ACh
atropine
muscarinic antagonist- tertiary amines, can be used in treating intoxication from cholinoceptor agonists
drug action for tx of myasthenia gravis
cholinomimetic -cholinesterase inhibitors, work on nicotinic receptors found at the neuromuscular junction, nonselective for muscarinic receptors
ex. neostigmine
What is the purpose of making derivatives of ACh?
can adjust the molecule to a) increase resistance** to degradation by acetylcholinesterase or b) change thespecificity** to make it more selective for certain receptors (muscarinic vs nicotinic)
ex. choline esters (change methyl group for NH2)
For each m uscarinic receptor subtype, list the primary location and dominant effector system:
M1, M2, M3 (most abundant)
M1: nerves, IP3 DAG,
M2: heart, nerves, smooth muscle, cAMP, K+ channel current
M3: glands, smooth muscle, ednothelium, IP3 DAG
- Note: M1 and M3 use Gq*
- M2 and M4 use Gi*
explain the differential effect of ACh on blood vessels with and without endothelial layer. What is the m echanism? (Ach acts on which receptor, whats the secondary signaling etc)
- “unrubbed” / endothelial layer in tact = blood vessel relaxation
- “rubbed off” / endothelial layer gone = blood vessel contraction
endothelial cells contain endothelial derived relaxation factor (EDRF) = nitric oxide = relaxation