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


RESULTS
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.


CONCLUSIONS
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.
Braasch
Daniel C
DC
Department of Biology and Program in Neuroscience, College of William and Mary, Williamsburg, Virginia 23187, USA. braasch@bu.edu
Deegan
Erin M
EM
Grimm
Eleanor R
ER
Griffin
John D
JD
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D007025:Anterior Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D001833:Body Temperature Regulation / Q000187:drug effects; D015740:Calcitonin Gene-Related Peptide / Q000494:pharmacology*; D004594:Electrophysiology / Q000295:instrumentation / Q000379:methods; D007032:Hypothalamus, Anterior / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008839:Microelectrodes; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011301:Preoptic Area / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012044:Regression Analysis; D013696:Temperature; D046509:Tissue Culture Techniques
D015740:Calcitonin Gene-Related Peptide