Glutamate injection into the suprachiasmatic nucleus stimulates brown fat thermogenesis in the rat.
Injection of glutamate (100 mM to 1 M, in 0.25 micrograms saline) into the hypothalamic suprachiasmatic nucleus (SCN) dose-dependently increased interscapular brown adipose tissue (IBAT) and core temperatures in the urethane-anaesthetized rat. This effect was more pronounced in rats tested during the light-off period than in animals tested during the light-on period. Prior injection of the local anaesthetic, procaine (5% in 0.5 microliter saline), into the ipsilateral ventromedial hypothalamic nucleus (VMH) attenuated the increases in IBAT and core temperatures induced by intra-SCN glutamate. The VMH has previously been implicated in the central regulation of BAT thermogenesis; the present results suggest the pathway arising in the SCN exerts an excitatory influence on VMH neurons involved in the control of BAT function.
Amir
S
S
Department of Psychology, Concordia University, Montreal, Que, Canada.
Shizgal
P
P
Rompré
P P
PP
D002001:Adipose Tissue, Brown / Q000378:metabolism*; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013493:Suprachiasmatic Nucleus / Q000187:drug effects / Q000502:physiology*
D005971:Glutamates; D018698:Glutamic Acid