1. Neuromuscular Pharmacology
Section 2, Lecture 1

2. Drugs change the function of Nervous System
Neurotransmitters
Synthesis
Storage
Release
Inactivation
Neuronal uptake
Receptors
Activate
block

3. Short preganglionic
Long postganglionic
Thoracic/ lumbar spinal chord
Discharge as a unit
High post : pre fiber ratio

4. Long preganglionic
Short postganglionic
Cranial nerves +some from the sacral spinal chord
Discrete activation of specific target tissues:
Low post : pre fiber ratio

5. Sympathetic and the Parasympathetic NS have opposing effects on organ function
rest & digest
Fight or flight

6. P S

7. P S

8. Neurotransmitters and Receptors
Acetylcholine (Ach)- in all autonomic parasymp. Junctions pre and post ganglionic
Norepinephrine (NE)- Symp. post ganglionic neuroeffector juncion
Epinephrine (E)- released from adrenal medulla in response to symp. activation
Other Neurotransmitters: neuropeptide Y, vasoactive intestinal polypeptide (VIP), enkephalin, substance P, NO, seretonin, ATP

9. Receptors for Ach, NE, and EP
Cholinergic receptors
Muscarinic (M):
Binds and activated by muscarine
Para sympathetic neuroeffector junctions
Nicotinic (N)
Activated by nicotine
Found in all autonomic ganglia and somatic neuromuscular junctions
Adrenergic receptors
Receptors for EP and NE
Sympathetic neuroeffector junctions
Two types:
a (a1, a2 ): Mediates smooth muscle contraction
b (b1 and b2): Mediates smooth muscle relaxation and cardiac stimulation

11. Choline acethytransferase
Nerve stimulation calcium influx
Removed by cholinesterase
(+)
Cholinesters
(Direct acting)
Bethanechol
Pilocarpine
Cholinesterase inhibitors
Indirect- acting

12. Tyrosine hydroxylase
Neuronal blocking agents block synthesis, storage and release
DA:Dopamine
NE: Norepinephrine
MAO: Monoamine oxidase
COMT: Cathecol-O-methyltransferase

13. Mechanism of physiological response by direct-acting sympathomimetics
Mechanism of physiological response by direct-acting sympathomimetics. D, Drug; NE, norepinephrine.

14. Mechanism of physiological response by indirect-acting sympathomimetics. D, Drug; NE, norepinephrine.

15. Mechanism of physiological response by mixed-acting sympathomimetics
Mechanism of physiological response by mixed-acting sympathomimetics. D, Drug; NE, norepinephrine.