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

This Article Full Text Full Text (PDF) All Versions of this Article: 288/3/R723    most recent 00669.2004v1 Alert me when this article is cited 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 (9) Citing Articles via Google Scholar Google Scholar Articles by Cao, W.-H. Articles by Morrison, S. F. Search for Related Content PubMed PubMed Citation Articles by Cao, W.-H. Articles by Morrison, S. F.

SLEEP AND TEMPERATURE REGULATION

Brown adipose tissue thermogenesis contributes to fentanyl-evoked hyperthermia

Neurological Sciences Institute, Oregon Health and Science University, Beaverton, Oregon

Submitted 29 September 2004 ; accepted in final form 23 November 2004

µ-Opioid receptor activation increases body temperature and affects cardiovascular function. In the present study, fentanyl was administered intravenously [100 µg/kg (300 nmol/kg) iv] and intracerebroventricularly [3.4 µg (10 nmol) in 10 µl icv] in urethane-chloralose-anesthetized, artificially ventilated rats. Increases in brown adipose tissue (BAT) sympathetic nerve activity (SNA) (peak, +326% of control), BAT temperature (peak, +0.8°C), renal SNA (peak, +146% of control), and heart rate (HR; peak, +32 beats/min) produced by intravenous fentanyl were abolished by premamillary transection of the neuraxis but were mimicked by intracerebroventricular administration of fentanyl, which also increased arterial pressure (AP; peak, +12 mmHg). Pretreatment with the opioid antagonist naloxone (100 nmol in 10 µl icv) eliminated the intracerebroventricular fentanyl-evoked responses. Microinjection of glycine (0.5 M, 60 nl) to inhibit local neurons in the rostral raphe pallidus (RPa) selectively reversed the intracerebroventricular fentanyl-evoked increases in BAT SNA and HR, while the fentanyl-evoked excitation in RSNA, the pressor responses, and the tachycardic responses were reversed by inhibition of neurons in the rostral ventrolateral medulla (RVLM). Prior inhibition of neurons in the dorsomedial hypothalamus eliminated the intracerebroventricular fentanyl-evoked increases in BAT SNA, BAT temperature, and HR, but not those in RSNA or AP. These results indicate that activation of central µ-opioid receptors with fentanyl can elicit BAT thermogenesis and cardiovascular stimulation through excitation of the sympathetic outflows to BAT, kidney, and heart. Activation of neurons in the rostral RPa and RVLM are essential for the increases in BAT thermogenesis and renal sympathoexcitation, respectively, induced by activation of central µ-opioid receptors. BAT thermogenesis could contribute to fentanyl-evoked hyperthermia, particularly in infants where BAT plays a significant role in thermoregulation.

renal sympathetic nerve; heart rate; arterial pressure; µ-opioid receptor; naloxone; raphe pallidus; dorsomedial hypothalamus; rostral ventrolateral medulla

This article has been cited by other articles:

				S. F. Morrison, K. Nakamura, and C. J. Madden Central control of thermogenesis in mammals Exp Physiol, July 1, 2008; 93(7): 773 - 797. [Abstract] [Full Text] [PDF]

				J. A. DiMicco and D. V. Zaretsky The dorsomedial hypothalamus: a new player in thermoregulation Am J Physiol Regulatory Integrative Comp Physiol, January 1, 2007; 292(1): R47 - R63. [Abstract] [Full Text] [PDF]

				J. A. DiMicco and D. V. Zaretsky The mysterious role of prostaglandin E2 in the medullary raphe: a hot topic or not? Am J Physiol Regulatory Integrative Comp Physiol, December 1, 2005; 289(6): R1589 - R1591. [Full Text] [PDF]

				W. W. Blessing BAT control shows the way: medullary raphe/parapyramidal neurons and sympathetic regulation of brown adipose tissue Am J Physiol Regulatory Integrative Comp Physiol, March 1, 2005; 288(3): R557 - R560. [Full Text] [PDF]