The model synaptic preparation of the crayfish opener neuromuscular junction is known to be responsive to exogenous application of 5-HT. The primary effect of 5-HT is an enhancement of vesicular release from the presynaptic motor nerve terminal. 5-HT is known to act through an IP3 cascade which suggests the presence of a 5-HT2 receptor subtype; however, this is based on vertebrate 5-HT receptor classification. We examined this possibility by using a selective agonist and two antagonists of the vertebrate 5-HT2 receptor subtypes. The antagonist ketanserin and spiperone reduce the responsiveness of 5-HT in a dose-dependent manner. The broad 5-HT2 receptor agonist, α-methyl-5-hydroxytryptamine (α-Me-5-HT) enhances synaptic transmission, in a concentration-dependent manner, but it is not as potent as 5-HT. These results support the notion that a 5-HT2 receptor subtype is present presynaptically on the crayfish motor nerve terminals. By knowing the types of 5-HT receptors present on the presynaptic motor nerve terminals in this model synaptic preparation, a better understanding of the mechanisms of action of 5-HT on vesicular release will be forthcoming.
|Number of pages||8|
|State||Published - Apr 5 2002|
Bibliographical noteFunding Information:
Funding was provided by NSF grants IBN-9808631 (RLC), NSF-ILI-DUE 9850907 (RLC) and a G. Ribble Fellowship for undergraduate studies in the School of Biological Sciences at the University of Kentucky (JT).
Copyright 2008 Elsevier B.V., All rights reserved.
ASJC Scopus subject areas
- Neuroscience (all)
- Molecular Biology
- Clinical Neurology
- Developmental Biology