PHAR 340 Lecture Notes - Lecture 29: H1 Antagonist, Myenteric Plexus, Gastric Mucosa
23 Dec 2018
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Document Summary
Mechanism bio sub syn near site of action and secreted locally over short duration, but can have systemic effects can be amine, peptide or lipid derived. Bio active amine in tissues sequestered and bound in granules (mast + basophils) + in brain (nt), formed by decarboxylation of l-histidine. His content reflects mast cell content (usually at sites of injury), his found in enterochromaffin like cells which act parietal cells. Natural compound found in mammalian sys, plants, venoms + stinging secretions. From mast cell stores when ige bind ag and cause degranulation, drugs (morphine/tubocurarine) diplace his from granules, chem + mech mast cell injury release his. H1: r on smooth muscle, endothelium + brain to incr ip3 + dag. H2: gastric mucosa, cardiac muscle, mast cells + brain to incr camp. H3: presynaptic, brain, myenteric plexus + other neurons to decr camp. H4: modulate prod of blood cells (eosino, neutron, cd4 t), decr camp.
