Rehnberg BG, Bates EH, Smith RJ, Sloley BD, Richardson JS. Brain benzodiazepine receptors in fathead minnows and the behavioral response to alarm pheromone.
Pharmacol Biochem Behav 1989;
33:435-42. [PMID:
2554343 DOI:
10.1016/0091-3057(89)90527-3]
[Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Fathead minnows (Pimephales promelas) exposed to 1 or 10 mg/l chlordiazepoxide showed normal alarm behavior during the presentation of alarm pheromone. Fish exposed to 20 mg/l drug, however, showed little or no behavioral alarm and did not appear sedated. A food extract stimulus presented after alarm pheromone led to a large foraging response by fish exposed to 20 mg/l chlordiazepoxide. Control fish or fish exposed to 1 to 10 mg/l drug showed less tendency to begin foraging. Exposure to 1, 10, or 20 mg/l chlordiazepoxide for 3 hr did not affect whole-brain concentrations of tryptophan, 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, tyrosine, or dopamine. The binding of [3H]diazepam to specific brain receptor sites (KD = 10 nM, estimated Bmax = 3.3 fmol/mg wet weight) could be displaced by chlordiazepoxide (IC50 = 1.6 microM). These results suggest that benzodiazepine receptors in the central nervous system of lower vertebrates may function in ways similar to those in mammals, i.e., in the modulation of behavior in anxiety-like states.
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