Calcitonin gene-related peptide alters the firing rates of hypothalamic temperature sensitive and insensitive neurons

• Published in: BMC neuroscience Vol. 9; no. 1; p. 64
• Main Authors: Braasch, Daniel C, Deegan, Erin M, Grimm, Eleanor R, Griffin, John D
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 11-07-2008; BioMed Central; BMC
• Subjects: Action Potentials - drug effects; Action Potentials - physiology; Animals; Anterior Hypothalamic Nucleus - cytology; Anterior Hypothalamic Nucleus - drug effects; Anterior Hypothalamic Nucleus - physiology; Body temperature; Body Temperature Regulation - drug effects; Calcitonin Gene-Related Peptide - pharmacology; Electrophysiology - instrumentation; Electrophysiology - methods; Hypothalamus; Hypothalamus, Anterior - cytology; Hypothalamus, Anterior - drug effects; Hypothalamus, Anterior - physiology; Male; Microelectrodes; Neural Pathways - drug effects; Neural Pathways - physiology; Neurons - cytology; Neurons - drug effects; Neurons - physiology; Peptides; Physiological aspects; Preoptic Area - cytology; Preoptic Area - drug effects; Preoptic Area - physiology; Rats; Rats, Sprague-Dawley; Regression Analysis; Temperature; Tissue Culture Techniques; United States
• ISSN: 1471-2202; 1471-2202
• DOI: 10.1186/1471-2202-9-64

Transient hyperthermic shifts in body temperature have been linked to the endogenous hormone calcitonin gene-related peptide (CGRP), which can increase sympathetic activation and metabolic heat production. Recent studies have demonstrated that these centrally mediated responses may result from CGRP dependent changes in the activity of thermoregulatory neurons in the preoptic and anterior regions of the hypothalamus (POAH).
Using a tissue slice preparation, we recorded the single-unit activity of POAH neurons from the adult male rat, in response to temperature and CGRP (10 muM). Based on the slope of firing rate as a function of temperature, neurons were classified as either warm sensitive or temperature insensitive. All warm sensitive neurons responded to CGRP with a significant decrease in firing rate. While CGRP did not alter the firing rates of some temperature insensitive neurons, responsive neurons showed an increase in firing rate.
With respect to current models of thermoregulatory control, these CGRP dependent changes in firing rate would result in hyperthermia. This suggests that both warm sensitive and temperature insensitive neurons in the POAH may play a role in producing this hyperthermic shift in temperature.