Role of mast cell histamine in brown adipose tissue thermogenic response to VMH stimulation.
Electrical stimulation of the ventromedial hypothalamic area in rats caused a significant but transient increase in interscapular brown adipose tissue temperature. This response was markedly reduced by cimetidine, a histamine H2-receptor antagonist, but not by pyrilamine, an H1-receptor antagonist. Histamine is present in substantial amounts within mast cells in brown adipose tissue as injections of compound 48/80, which cause degranulation of connective tissue mast cells, reduced the tissue histamine content by > 85%. In contrast, histamine content in brown adipose tissue was not affected by loss of sympathetic neural input (with 6-hydroxydopamine) or sensory neural input (with capsaicin). Neither cimetidine nor histamine had any effect on basal and norepinephrine-stimulated rates of O2 consumption by isolated brown adipocytes. These results indicate that histamine released from mast cells acting on H2-receptors may play an important but indirect role in the thermogenic response of brown adipose tissue to stimulation of the ventromedial hypothalamic area.
Desautels
M
M
Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Wollin
A
A
Halvorson
I
I
Muralidhara
D V
DV
Thornhill
J
J
D017667:Adipocytes / Q000378:metabolism; D002001:Adipose Tissue, Brown / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D001833:Body Temperature Regulation / Q000502:physiology*; D002927:Cimetidine / Q000494:pharmacology; D004558:Electric Stimulation; D005260:Female; D006632:Histamine / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology*; D008297:Male; D008407:Mast Cells / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D011738:Pyrilamine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D014697:Ventromedial Hypothalamic Nucleus / Q000502:physiology*
D002927:Cimetidine; D006632:Histamine; D011738:Pyrilamine; D009638:Norepinephrine