Behavioral evidence for supersensitivity following destruction of central serotonergic nerve terminals by 5,7 dihydroxytryptamine

M. E. Trulson, E. E. Eubanks, Barry Jacobs

Research output: Contribution to journalArticlepeer-review

171 Scopus citations

Abstract

Previous studies have established that a complex behavioral syndrome consisting of tremor, rigidity, hindlimb abduction, Straub tail, lateral head weaving and reciprocal forepaw treading is a specific reflection of the activity of central serotonin receptors. This syndrome was utilized in the present study to test for supersensitivity in the central serotonergic system. Specific destruction of central serotonin nerve terminals by intraventricular injection of 5,7 dihydroxytryptamine (5,7 DHT, 50 μg) in adult male rats pretreated with a catecholamine uptake blocking agent resulted in marked supersensitivity to serotonin precursors and agonists. The greatest degree of supersensitivity was observed in response to L 5 hydroxytryptophan, for which the ED50 for elicitation of the syndrome was 20% of the value for control rats. A lesser degree of supersensitivity was seen in response to L tryptophan (following monoamine oxidase inhibition) and the direct acting serotonin agonist, 5 methoxy N,N dimethyltryptamine, for which the ED50 was approximately 50% of the control value in both cases. Supersensitivity begins to develop within 24 hours and is relatively complete by 96 hours after 5,7 DHT. A marked subsensitivity to the serotonin releasing agent, fenfluramine, was found in 5,7 DHT treated rats. In contrast to the marked supersensitivity to serotonin precursors and agonists which occurs following 5,7 DHT, chronic administration of a serotonin synthesis inhibitor, p chlorophenylalanine (400 mg/kg every 3 days for a total of 24 days), did not produce supersensitivity to L 5 hydroxytryptophan or 5 methoxy N,N dimethyltryptamine. Possible pre and postsynaptic mechanisms for the development of supersensitivity are discussed.

Original languageEnglish (US)
Pages (from-to)23-32
Number of pages10
JournalJournal of Pharmacology and Experimental Therapeutics
Volume198
Issue number1
StatePublished - Dec 1 1976

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmacology

Fingerprint Dive into the research topics of 'Behavioral evidence for supersensitivity following destruction of central serotonergic nerve terminals by 5,7 dihydroxytryptamine'. Together they form a unique fingerprint.

Cite this