Davies, Michael, Wilkinson, Lawrence Stephen ORCID: https://orcid.org/0000-0002-9337-6124 and Roberts, Malcolm H.T. 1988. Evidence for depressant 5-HT1-like receptors on rat brainstem neurones. British Journal of Pharmacology 94 (2) , pp. 492-499. 10.1111/j.1476-5381.1988.tb11552.x |
Abstract
1 The technique of microiontophoresis was used to evaluate the contribution of 5-HT1-like, 5-HT2- and 5-HT3-receptors to the depressant effects of 5-hydroxytryptamine (5-HT) on neurones in the midline of the medullary brainstem of the rat in vivo. 2 Depressant responses to 5-HT were resistant to antagonism by the 5-HT2-receptor antagonist ketanserin and the 5-HT3-receptor antagonist MDL 72222 applied either microiontophoretically or administered systemically. 3 Microiontophoretic or systemic administration of the 5-HT antagonist metergoline, which shows nanomolar affinity for the 5-HT1-binding site, also failed to attenuate the depressant responses to 5-HT. 4 Systemic administration of high doses of methysergide (30–40 mg kg−1) attenuated the depressant responses to 5-HT but did not block depressant responses to GABA or excitatory responses to glutamate. 5 The depressant effects of 5-HT were potently mimicked by the 5-HT1-like receptor agonists 5-carboxamidotryptamine and 8-OH-DPAT. 6 These results indicate that neither 5-HT2-receptors nor 5-HT3-receptors are involved in the depressant effects of 5-HT on midline brainstem neurones. The depressant effects of 5-carboxamidotryptamine (5-CT) and 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) and blockade of the response to 5-HT by high doses of methysergide suggests the involvement of 5-HT1-like receptors. The lack of effect of metergoline, however, indicates that this receptor may be different from any of the 5-HT1 binding sites yet described.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | MRC Centre for Neuropsychiatric Genetics and Genomics (CNGG) Medicine Neuroscience and Mental Health Research Institute (NMHRI) Psychology |
Subjects: | R Medicine > R Medicine (General) |
Publisher: | Nature Publishing Group |
ISSN: | 0007-1188 |
Last Modified: | 31 Oct 2022 10:36 |
URI: | https://orca.cardiff.ac.uk/id/eprint/85457 |
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