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Neuropeptides modulate rat chorda tympani responses.
S A Simon1, Lieju Liu, Robert P Erickson
1Department of Neurobiology, Duke University, Durham, North Carolina 27710, USA. sas@neuro.duke.edu
Summary
Cholecystokinin-8 (CCK-8) and calcitonin gene-related peptide (CGRP) alter rat chorda tympani (CT) nerve responses to salt and acid. These neuropeptides modulate taste perception by affecting CT nerve activity.
Area of Science:
- Neuroscience
- Sensory Physiology
- Gastroenterology
Background:
- The neuropeptide leptin modulates rat chorda tympani (CT) responses to sweet tastes.
- Investigating other neuropeptides' effects on gustatory neural pathways is crucial for understanding taste modulation.
Purpose of the Study:
- To determine if cholecystokinin-8 (CCK-8), substance P(4-11) (SP(4-11)), or calcitonin gene-related peptide (CGRP) modulate rat CT nerve responses to various tastants.
- To examine the effects of neuropeptides on initial CT nerve responses to NaCl, HCl, quinine HCl, and sucrose.
Main Methods:
- Rat whole nerve CT responses were measured.
- Peptides (CCK-8, SP(4-11), CGRP) were administered via the ipsilateral lingual artery (LA) to study short-latency effects.
- Tastants included NaCl, HCl, quinine HCl, and sucrose.
Main Results:
- CCK-8 increased CT responses to NaCl and HCl.
- CGRP decreased CT responses to NaCl and HCl.
- SP(4-11) showed no significant effect on CT responses.
- Peptide-induced changes in responses to quinine HCl and sucrose were minimal and difficult to detect.
Conclusions:
- Neuropeptides can rapidly modulate CT nerve responses in a peptide-specific manner.
- Local administration via the lingual artery allows for the study of short-latency neuropeptide effects on taste pathways.
- CCK-8 and CGRP exhibit distinct modulatory effects on salt and acid taste perception in rats.