Behavioral Neuroscience, JAR lecture on Acetylcholine
USD Department of Biology
Behavioral Neuroscience
Electric Fish and JAR Behavior
Afferent Path of Electroreception
Control of Electric Organ Discharge
Efferent Output producing EOD
Jamming Avoidance Response
Electric field Glutamate
Electric Fish Figures
Electric Fish Circuitry
Acronyms/Abbreviations    end
Jamming  Acetylcholine (ACh)  
		        I I
	A. substrates: choline and acetyl CoA
	                 (diet)     (Glycolysis and Kreb's)
		1. synthetic enzyme: choline acetyltransferase (CAT)

			a. cytosolic   (most is synaptic)

			b. CoA left over

		2. degradative enzyme: acetylcholine esterase (AChE)

			a. membrane protein

			b. catabolites = choline and acetate
				i. reuptake of choline

			c. turnover = 150ms	or	5,000 ACh molecules/s

	B. Muscarinic and Nicotinic Receptors 	(membrane proteins)

		1. muscarinic M1 - M5    7tm

			a. slow response time (100 - 250 ms)

			b. act directly on ion channels 	

				i. open or close K+, Ca++, or Cl- channels

					(1) may lead to depolarization 
					   or hyperpolarization

			c. and activate 2nd messenger system (via G proteins)
				i. M1,3,5 Gp(q)асPLCасPIP2асIP3 & Ca++

				ii. M2,4 GiатACатcAMP ат PKA

		2. Nicotinic

			a. made up of 5 subunits, from these a, b, g, d, e
				i. four glycosylated peptide chains a, b, g, d in muscle
				ii. neuronal only a & b

			b. ACh binds to the a subunit

				i. binding causes conformational change

					(1) allows cations, not anions, to pass

					(2) Ca++ passing stimulates muscular contraction
					     of trunk, fin, oculomotor, jaw & opercular 
	C. Central ACh Distribution in vertebrates: Involved in Learning
		1. ACh is produced in the nucleus basalis 

			a. projections to the cerebral cortex and many parts of the brain

			b. these cells degenerate during Alzheimer's disease

		2. ACh is in 2 specific populations in the limbic system

			a. septum to hippocampus  & habenulo-endopeduncular projections

			b. short axon striatal cells
	D. Autonomic NS
		1. all sympathetic and parasympathetic preganglionic neurons

		2. parasympathetic postganglionic neurons

	E. ACh as a transmitter for motor actions and coordination
		1. motor neurons 
		\ all skeletal neuromuscular junctions
			a. Invertebrate motor neurons
			b. Vertebrate motoneurons of spinal cord & cranial nerves (I-XII)
				i. abducens (VI) innervation of the eye
				ii. trigeminal (V) innervation of the operculum
		2. Cells in the caudate-putamen nucleus involved in motor coordination 
		3. PPT (pedunculopontine tegmental nucleus) and LDT (laterodorsal tegmental nucleus)
			innervation of substantia nigra

VI. Efferent output producing EOD