Behavioral Neuroscience Summers |
Turtle Eyeblink Behavior Sensory Stimulation of Eyeblink Eyeblink Motor Output Neuromuscular Function In vitro Conditioning |
text:Kandel pages 1243 & 849 and Nestler pages 200-208 Glu ACh BDNF Turtles and Ecology Eyeblink Circuitry end Acronyms/Abbreviations Syllabus |
Eyeblink Conditioning V. Acetylcholine (ACh) O I I (CH3)3N+-CH2-CH2-O-C-CH3 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)асPLCасIP3 & Ca++ ii. M2,4 GiатACатcAMP ат PKA 2. Nicotinic a. four glycosylated peptide chains a, b, g, d in muscle b. neuronal only a & b c. 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 pyramidalis, lateral rectus, retractor bulbi causing blinking of nictitating membrane 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. Vertebrates motoneurons of the spinal cord and cranial nerves i. abducens innervation of 2. Cells in the caudate-putamen nucleus involved in motor coordination 3. PPT and LPT innervation of substantia nigra