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Main Title Serotonergic Modulation of the Acoustic Startle Response in Rats during Preweaning Development.
Author Sheets, L. P. ; Cook, L. L. ; Reiter, L. W. ;
CORP Author Health Effects Research Lab., Research Triangle Park, NC.
Publisher c1989
Year Published 1989
Report Number EPA/600/J-89/337;
Stock Number PB90-201674
Additional Subjects Serotonin ; Biogenetic amines ; Graphs(Charts) ; Nerve cells ; Reprints ; Startle reaction ; Ontongeny ; Weaning ; Acoustic stimulation ; Dose-response relationships ; Tetrahydronaphthalenes ; Serotonin receptors ; Serotonin antagonists
Library Call Number Additional Info Location Last
NTIS  PB90-201674 Some EPA libraries have a fiche copy filed under the call number shown. 07/26/2022
Collation 10p
The involvement of serotonin (5-HT) in modulating the acoustic startle response (ASR) is well established in adult rats, but 5-HT involvement during the preweaning period, when 5-HT neurons undergo extensive development, has not previously been described. Three 5-HT receptor subtypes are reported to modulate the ASR in adult rats: 5-HT1A and 5-HT2 receptor agonists facilitate the ASR, whereas 5-HT1B agonists decrease the response. In the present study, the effects of 5-HT agonists and generalized 5-HT depletion on the ASR were studied in preweanling animals, using independent groups of Long-Evans rats tested on postnatal day (PND) 13, 17 and 21. 8-Hydroxy-2-(di-n-propylamino) tetralin (8OHDPAT, 62-1000 microg/kg), a 5-HT1A receptor agonist, and 5-methoxy-N,N-dimethyl tryptamine (MeODMT, 2-4 mg/kg), a nonselective 5-HT agonist, had no effect on PND 13 and then increased the ASR on PND 17 and 21. The 5-HT2 receptor antagonists cyproheptadine (5 mg/kg) and ketanserin (5 mg/kg) blocked the effect of MeODMT at both ages, providing some evidence that MeODMT increased the ASR through 5-HT2 receptors. The failure of PCPA to increase the ASR in preweanling rats tends to indicate that 5-HT tonic inhibition has not developed by PND 21. The results with PCPA are inconclusive, however, since there is some discrepancy regarding the effect of PCPA on the ASR in adult rats. (Copyright (c) 1989 Pergamon Press.)