Intro to Autonomic Pharmacology Flashcards
All Parasympathetic postganglionic fibers are ________. They release _____ which acts on ______.
Cholinergic, Acetylcholine, muscurinic receptors
All preganglionic efferent autonimc fibers and Somatic motor fibers to skeletal muscles release _____. Which Act on ______.
Acetylcholine, Nicotinic receptors
All postganglionic sympathetic fibers except 1 release _______ which can act on either _______ or _______. they are _________.
What is the exception? what does it act on? Which tissue thing?
norepinephrine, Alpha or Beta adrenoreceptors. They are noradrenoergic
Exception: acetylcholine release on muscurinic receptors supplying sweat glands
What are some other secretions by sympathetic fibers?
Dopamine, Epinephrine, Norepinephrine
Cholinergic and Adrenergic Transmission
LOOK AT THE SLIDES. THE PICTURES ARE WAY BETTER THAN EXPLAINING IT.
2 types of Cholinergic receptors and describe them
Nicotinic: ligand gated ion channels. cause increase permeability to Na+ and Ca2+. (Depolarization and excitation) Nn=Neuronal Nm=muscle
Muscurinic: innervated by mostly PNS and the rare SNS.
M1: CNS and autonomic ganglia. Excitatory effects
M2: Heart, presynaptic terminals on neurons. Inhibitory effect open K channels and inhibit Ca channels. Responsible for vagal inhibition of the heart.
M3: smooth muscle contraction and secretory gland secretions. Excitatory They do have an inhibitory aspect by causing vascular smooth muscle relaxation through NO released by endothelial cells. (no innervation by neurons for the vasculature but the M3 receptors are there)
*nice table in lecture notes summarizing this
2 types of Adrenergic receptors and be able to describe them
Alpha and Beta
A1=excitatory
A2: inhibitory
B1 excitatory, 2 inhibitory, 3
*look at the table in the lecture notes. Way better seen than typed
Presynaptic Modulation of Acetylcholine Release
- ACh release inhibited by ACh bind to M2 and NE binding to Alpha2
- Other inhibitory receptors like A1, H3, and opioid receptors
- Also there are Beta 2 presynaptic receptors
Presynaptic Regulation of NE Release
Feed back to Alpha 2 and inhibit itselfs further release
- M2, 5-HT, PGE2, Histamine, Enkephalin and DA receptors can inhibit NE release
- Stimulate more release by activating Beta 2 presynaptic receptors along with angiotensin 2 receptors
Central Integration of Autonomic activity
Midbrain/Medulla integrate the sensory with higher cortical center information
- Sensory info from PSNS can cause reflex and move motor muscles in the sympathetic system
- *Sensory Carotid sinus baroreceptor fibers in the glossopharyngeal nerve have a major influence on sympathetic outflow from the vasomotor center.
Integration of cardiovascular function
- primary control of CV function is mean arterial pressure
- any small change from anywhere in the body that affects this will evoke a powerful homeostatic secondary responses that compensates for the change
- Ex: NE infusion. Its a vasoconstrictor causing increased vascular resistance which increases mean arterial pressure. It naturally would cause an increased heart rate and contractile force due to the Beta 1 receptors. however there is a reflex control to PSNS to slow the heart and decrease sympathetic outflow. Its PARADOXICAL. NE SLOWS THE HEART
Pharmacology of the Eye
- 3 receptors and 4 effects
- inhibitory drug of M receptors
Alpha 1: pupil dilation: Mydriasis (use phenylephrine)
M3: Pupil constriction: Miosis (Muscurinic effects)
M3: Contract ciliary muscles to focus close (adds pressure to trebecular meshwork opening the pores and facilitating outflow of the Aq Humor into the canal of schlemm. useful in glaucoma to decrease intraocular pressure
Beta2: Secretory epithelium of ciliary body to produce aqueous humor (Block Beta 2 to reduce intraocular pressure, useful in glaucoma)
*Atropine inhibits/reverses effects of M
Define Cyclospasm
Marked Contraction of the ciliary muscle
