HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Free Full Text (PDF) Free All Versions of this Article: 98/4/1458    most recent 00916.2004v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (13) Citing Articles via Google Scholar Google Scholar Articles by Hasegawa, H. Articles by Meeusen, R. Search for Related Content PubMed PubMed Citation Articles by Hasegawa, H. Articles by Meeusen, R.

Inhibition of the preoptic area and anterior hypothalamus by tetrodotoxin alters thermoregulatory functions in exercising rats

¹Laboratory of Exercise Physiology, Faculty of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima; ²Department of Biology, Graduate School of Science, Tokyo Metropolitan University, Hachioji, Tokyo, Japan; and ³Department of Human Physiology and Sportsmedicine, Vrije Universiteit Brussel, Brussels, Belgium

Submitted 31 August 2004 ; accepted in final form 17 December 2004

We have previously demonstrated a functional role of the preoptic area and anterior hypothalamus (PO/AH) in thermoregulation in freely moving rats at various temperature conditions by using microdialysis and biotelemetry methods. In the present study, we perfused tetrodotoxin (TTX) solution into the PO/AH to investigate whether this manipulation can modify thermoregulation in exercising rats. Male Wistar rats were trained for 3 wk by treadmill running. Body core temperature (T_b), heart rate (HR), and tail skin temperature (T_tail) were measured. Rats ran for 120 min at speed of 10 m/min, with TTX (5 µM) perfused into the left PO/AH during the last 60 min of exercise through a microdialysis probe (control, n = 12; TTX, n = 12). T_b, HR, and T_tail increased during the first 20 min of exercise. Thereafter, T_b, HR, and T_tail were stable in both groups. Perfusion of TTX into the PO/AH evoked an additional rise in T_b (control: 38.2 ± 0.1°C, TTX: 39.3 ± 0.2°C; P < 0.001) with a significant decrease in T_tail (control: 31.2 ± 0.5°C, TTX: 28.3 ± 0.7°C; P < 0.01) and a significant increase in HR (control: 425.2 ± 12 beats/min, TTX: 502.1 ± 13 beats/min; P < 0.01). These results suggest that the TTX-induced hyperthermia was the result of both an impairment of heat loss and an elevation of heat production during exercise. We therefore propose the PO/AH as an important thermoregulatory site in the brain during exercise.

thermoregulation; heat dissipation; heat production; microdialysis

This article has been cited by other articles:

				L. Nybo Hyperthermia and fatigue J Appl Physiol, March 1, 2008; 104(3): 871 - 878. [Abstract] [Full Text] [PDF]

				L. H. R. Leite, A. C. R. Lacerda, U. Marubayashi, and C. C. Coimbra Central angiotensin AT1-receptor blockade affects thermoregulation and running performance in rats Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2006; 291(3): R603 - R607. [Abstract] [Full Text] [PDF]

				H. Hasegawa, R. Meeusen, S. Sarre, M. Diltoer, M. F. Piacentini, and Y. Michotte Acute dopamine/norepinephrine reuptake inhibition increases brain and core temperature in rats J Appl Physiol, October 1, 2005; 99(4): 1397 - 1401. [Abstract] [Full Text] [PDF]