BIOL 1117 Lecture Notes - Lecture 4: Monoamine Oxidase, Neuropeptide Y, Cardiac Muscle
3 Oct 2017
School
Department
Course
Professor
Document Summary
Norepinephrine (ne: ne is secreted by nearly all sympathetic postganglionic neurons: a few sympathetic post ganglionic neurons secrete ach which bind to receptors on target cell. Beta-adrenergic receptors: usually inhibitory, 3 subclasses with different effects, but act through g protein stimulation of camp as a second messenger ( 1, 2, 3) increases camp levels in postsynaptic cells with various effects, for ex. B2 cause smooth muscle to relax (inhibitory) in walls of bronchioles (bronchodilation) and walls of blood vessels (vasodilation) to cardiac muscle and skeletal muscle. Vasodilation: increased blood flow causes increased secretion. Vasoconstriction: decreased blood flow causes decreased secretion sympathetic effects tend to last longer than parasympathetic effects. Ach released by parasympathetics is broken down quickly at synapse. Ne by sympathetics is reabsorbed by nerve (reused or broken down by monoamine oxidase), diffuses to adjacent tissues, and much passes into bloodstream: circulates and has a prolonged effects: ans fibers releases other neurotransmitters such as neuropeptides.
