Electrical stimulation of the lower midbrain around retrorubral field decreases temperatures of brown fat and rectum in anesthetized Wistar rats.
To investigate a neuronal mechanism controlling heat production of brown adipose tissue (BAT), ventral regions of the lower midbrain was stimulated by rectangular electric current (0.1 ms, 1 mA, 5-50 Hz) while recording temperatures of the interscapular BAT (IBAT), rectum and arterial blood pressure in urethane-anesthetized Wistar rats at room temperature of 24-26 degrees C. Unilateral stimulation (10 Hz) for 5 min to the midbrain around the retrorubral field decreased temperatures of IBAT (0.33 +/- 0.03 degrees C, n = 33) and rectum (0.10 +/- 0.01 degrees C). The response was reversed when procaine (10%, 800 nl) was injected into the same locus. The results support the hypothesis that a tonic inhibitory mechanism for metabolic heat production locates around the retrorubral field.
Hashimoto
M
M
Department of Physiology, Yamanshim Medical University, Nakakoma, Yamanashi, Japan. masaakih@res.yamanashi-med.ac.jp
Arita
J
J
Shibata
M
M
D002001:Adipose Tissue, Brown / Q000378:metabolism / Q000502:physiology*; D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D001831:Body Temperature / Q000502:physiology*; D001833:Body Temperature Regulation / Q000502:physiology; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D005260:Female; D008297:Male; D008636:Mesencephalon / Q000502:physiology*; D008845:Microinjections; D011343:Procaine / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D012007:Rectum / Q000502:physiology; D012012:Red Nucleus / Q000502:physiology*; D013238:Stereotaxic Techniques
D011343:Procaine