Summers

Neurobiology text: Principles of Neural Science - Kandel, Schwartz and Jessell: Read pages 280-286 for this lecture end

XX. Central Anatomy of Monoamines and ACh 			back to XIX. Indoleamines

	A. Serotonin

		1. produced in the raphe nuclei and the medulla (MSG): B1-B9

			a. project to forebrain, cerebellum and spinal cord
			  (also found peripherally- especially blood platelets and intestine of almost every animal species;
			      also venom of amphibians, wasps, scorpions, sea anemone; also octopus salivary glands,
				  pineapples and bananas)

				i. pattern is widespread; similar to NE

					(1) widespread influence over arousal, sensory 
					    perception, emotion, & higher cognitive functions

						(a) pain suppression, sleeping & circadian rhythms,
						    thermal regulation, corticosteroid receptivity

						(b) LSD blocks some 5-HT receptors, stimulates 
						    others and inhibits raphe cells

						(c) 5-HT1A presynaptic = anxiolytic

							(i) many antidepressant drugs are 5-HT
							    reuptake blockers & work via
								5-HT1A presynaptically 
						
						
						(d) 5-HT1A postsynaptic = anxiogenic
						
						
						(e) 5-HT2 anxiogenic
							

	B.  DA is synthesized in the substantia nigra and ventral tegmental
	    area of the mesencephalon (midbrain)    	
											
		1. SN (A9) axons project to the caudate-putamen (striatum)

			a. mesostriatal  (nigrostriatal) system:  necessary for coordinated movmement

			b. degenerate during Parkinson's


		2. VTA (A10) axons have mesolimbic projections, ie. to limbic
		   structures inclucing: amygdala, olfactory tubercle, septal area,
		   and nucleus accumbens

			a. emotion, aggression

			b. mesocortical: prefrontal cortex - cognition

		3. short axon DA cells in arcuate nucleus of the hypothalamus (A11-15),
		   retina, olfactory bulb (A16), superior colliculus of the optic tectum,
		   retina (A17) and around the 4th ventricle

			a. ARC nucleus DA modulates Releasing Hormone secretion

	C. NE is synthesized in the locus ceruleus (for its bluish appearance)					  
 
		1. few cells in the medulla, but broad projections with extensive
		   collaterals and dense terminal arborizaitons in the cerebral cortex,
		   cerebellum, and spinal cord

			a. few terminals within a given region - NE secreted diffusely

				i. neuromodulatory

					(1) e.g. increase excitability of Hippocampal cells (b)

						(a) NE is secreted during aggressive behavior

					(2) or decrease cortical excitability (a)

		2. NE cells in the lateral tegmental area project to the thalamus,
		   hypothalamus, brainstem and spinal cord    

			a. regulation of releasing hormones

			b. integration of autonomic function

				i. projections to nuclei of solitary tract, dorsal vagus, and
				   intermediolateral column

					(1) activate parasympathetic decreases in HR and BP

		3. also secreted by the postganglionic neurons of the
		   sympathetic nervous system

	D. central Epinephrine is secreted from clusters of cells in the medulla

		1. intermingled with NE cells of lateral tegmentum (C1 = Epi cells)

			a. project to diencephalon

		2. dorsal medulla (C2 + C3) with NE cells of the LC

			a. project to spinal cord (C2),dorsal motor nuclei of vagus (C3),and
			   nuclei of the solitary tract (cranial nerves VII = facial,
			   IX = glossopharuyngeal, X = vagus)

				i. motor control of visera and taste from tongue

	E. Besides spinal motor and autonomic preganglionic soma, ACh is found
	   centrally in the basal forebrain and mesencephalon

		1. septal nuclei project to the hippocampus and limbic association area
		
			a. nucleus basalis cells project to mediotemporal cortex

				i. areas associated with memory

					(1) lost with CAT loss in Alzheimer's

		2. pedunculopontine and laterodorsal tegmental nuclei project to thalamus
		   and to pontine and medullary reticular formations and cranial nerve nuclei

XXI. Amino Acid Transmitters

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