Autonomic neurotransmitters; Physiology of smooth muscle Flashcards
What is the function of the autonomic nervous system?
- regulation of nonconscious “autonomic” functions
- homeostasis of the body
What are the divisions of the autonomic nervous system?
- parasympathetic
- sympathetic
- enteric nervous system
What is the general scheme of the ANS?
Preganglionic neuron
(CNS)
↓
post-ganglionic neuron
(periperal ganglion)
↓
target cell
What is the origin, ganglion, pre/post ganglionic axon of the parasympathetic nervous system?
Origin: Cranial nerves (III, VII, IX, X)
Sacral spinal cord (S2-S4)
Ganglion: near or within the organ
Preganglionic axon: long
postganglionic axon: short
What is the origin, ganglion, pre/post ganglionic axon of the sympathetic nervous system?
Origin: Thoracic spinal cord (T1-T12)
Lumbar spinal cord (L1-L2/3)
Ganglion: close to the spinal chord (pre/post vertebral ganglia)
Preganglionic axon: short
Postganglionic axon: long
What are the PREGANGLIONIC AXON transmitters and receptors of the parasympathetic and sympathetic NS?
Preganglionic axon transmitter: ACh
Preganglionic axon receptor: nAChR (nicotinic)
What are the POSTGANGLIONIC AXON transmitters and receptors of the parasympathetic NS?
Postganglionic axon Transmitter: ACh (VIP, NO)
Receptors of the effector cells:
mAChR(M1-M5)
M1,M3,M5 (IP3, Ca2+) M2,M4 (cAMP ↓)
What are the POSTGANGLIONIC AXON transmitters and receptors of the sympathetic NS?
Postganglionic axon Transmitter:
NE, ACh
NE-NPY – GI vessels NE-somatostatin
Receptors of the effector cells:
Adrenergic receptors
- alpha* 1 (IP3, Ca2+)
- alpha* 2 (cAMP↓)
- beta* 1 (cAMP↑)
- beta* 2 (cAMP↑)
- beta*3 (cAMP↑)
mAChR