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Evidence that 5‐hydroxytryptamine release in rat dorsal raphé nucleus is controlled by 5‐HT 1A , 5‐HT 1B and 5‐HT 1D autoreceptors
Author(s) -
Davidson Colin,
Stamford Jonathan A.
Publication year - 1995
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1995.tb13321.x
Subject(s) - agonist , autoreceptor , 5 ht receptor , dorsal raphe nucleus , serotonin , endocrinology , medicine , 5 ht1 receptor , chemistry , receptor antagonist , antagonist , receptor , metergoline , biology , serotonergic
Electrically stimulated 5‐hydroxytryptamine (5‐HT) release was monitored in slices of rat dorsal raphé nucleus (DRN) by fast cylic voltammetry. Pseudo‐single pulse stimulations (5 pulses at 100 Hz) were used to enable the effect of various receptor agonists to be seen without competition from endogenously released transmitter. The selective 5‐HT 1A receptor agonist, (+)‐8‐OH‐DPAT (1.0 μ m ) decreased stimulated 5‐HT release to 31 ± 3% of controls. This decrease was inhibited by the 5‐HT 1A receptor antagonists, (+)‐WAY‐100135 (1.0 μ m ) and WAY‐100635 (0.1 μ m ) but not by the 5‐HT 1D/B antagonist, GR127935 (0.05 μ m ). The selective 5‐HT 1B receptor agonist, CP‐93129 (0.3 μ m ) decreased stimulated 5‐HT release to 61 ± 4% of control. This effect was antagonized by the 5‐HT 1B receptor antagonist, isamoltane (0.5 μ m ) but not by (+)‐WAY‐100135. The 5‐HT 1D agonist, sumatriptan (0.5 μ m ) decreased stimulated 5‐HT release to 52 ± 2 % of controls. This decrease was blocked by GR‐127935 but not by WAY‐100635. These results suggest that 5‐HT release in the rat DRN is under the control of 5‐HT 1A , 5‐HT 1B and 5‐HT 1D autoreceptors.