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Release-regulating serotonin 5-HT1D autoreceptors in human cerebral cortex
G Maura1, S Thellung, G C Andrioli
1Istituto di Farmacologia e Farmacognosia, Università degli Studi di Genova, Italy.
Journal of Neurochemistry
|March 1, 1993
Summary
Human brain serotonin (5-HT) autoreceptors, unlike rat brains, are not 5-HT1B. Our study identifies these human autoreceptors as the 5-HT1D subtype, clarifying their pharmacological profile.
Area of Science:
- Neuropharmacology
- Serotonin receptor research
Background:
- Serotonin (5-HT) autoreceptors regulate neurotransmitter release.
- Rat brain 5-HT autoreceptors are primarily 5-HT1B subtype.
- Human brain 5-HT1B receptors are reportedly absent, necessitating characterization of human autoreceptors.
Purpose of the Study:
- To pharmacologically characterize 5-HT autoreceptors in the human brain.
- To determine the specific subtype of 5-HT autoreceptors in human neocortex.
Main Methods:
- Preparation of synaptosomes from human neocortex biopsy samples.
- Labeling synaptosomes with [3H]5-HT.
- Superfusion experiments using selective 5-HT receptor agonists and antagonists during K+ depolarization to measure [3H]5-HT overflow.
Main Results:
- Agonist potency order for inhibiting [3H]5-HT overflow: 5-HT > sumatriptan (5-HT1D/1B) > 8-hydroxy-2-(di-n-propylamino)tetralin (5-HT1A/1D) >> 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCl (5-HT2/1C).
- 5-HT effects were insensitive to ketanserin (5-HT2) but antagonized by methiothepin (5-HT1/2) and metergoline (5-HT1C/1D).
Conclusions:
- The pharmacological profile of human brain 5-HT autoreceptors is consistent with the 5-HT1D subtype.
- This finding differentiates human 5-HT autoreceptor pharmacology from that of the rat.