PSYCH 119A Lecture Notes - Lecture 11: Tryptophan Hydroxylase, Vesicular Monoamine Transporter 2, Metabotropic Receptor
Document Summary
Turnitin link will be set up today--deadline is class time. Mostly metabotropic receptor subtypes, only one ionotropic. Overwhelming amount of research focuses on 5ht1a, 5ht2a, 5ht1c. Tryptophan [tryptophan hydroxylase] 5-hydroxytryptophan [aromatic amino acid decarboxylase] serotonin. Blocks 5-ht by irreversibly inhibiting tryptophan hydroxylase. One or two high doses (250-500 mg/kg) of pcpa can reduce brain 5-ht levels in rats 80-90% for a long time. L-tryptophan can cross bbb, then have enzymatic process to produce 5-ht in the brain. L-tryp competes with large neutral amino acids for entry into the brain. Dietary tryptophan depletion leads to relapse in recovered depressed patients. Acute tryptophan depletion : higher self-rating of sadness when given tryptophan-containing mixture. 5-ht is also important in operant learning. Across species, 5-ht supports all kinds of appetitive operant learning. In presynaptic terminal and in the synapse. 5-ht could activate autoreceptor to slow down release. Could be taken back into presynaptic neuron by sert (serotonin transporter)
