Activation of GABAA receptor in the brain suppresses neostigmine or histamine-induced central nervous system-mediated hyperglycemia.
We investigated the effect of GABA receptor agonists on the central nervous system (CNS)-mediated hyperglycemia induced by neostigmine or histamine in anesthetized fed rats. The injection of muscimol, GABAA receptor agonist (1, 2.5 nmol) into the third cerebral ventricle suppressed the hyperglycemia induced by intraventricular injection of neostigmine (1 x 10(-8) mol) or histamine (5 x 10(-7) mol). Baclofen, GABAB receptor agonist (1, 2.5 nmol), however, did not suppress these hyperglycemia. Neither muscimol nor baclofen (2.5 nmol) affected plasma glucose levels. These findings suggest that activation of GABAA receptor in the CNS suppresses the hyperglycemia induced by the stimulation of cholinoceptive neuron or histaminergic neuron, but activation of GABAB receptor does not affect them.
Third Department of Internal Medicine, Nagoya University School of Medicine, Japan.
K
K
Nonogaki
X
X
Li
K
K
Ozawa
H
H
Miura
G
G
Watanabe
Y
Y
Hiyoshi
T
T
Tamagawa
N
N
Sakamoto
A
A
Iguchi
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D001921:Brain / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure*; D002490:Central Nervous System / Q000187:drug effects / Q000502:physiology*; D006632:Histamine; D006633:Histamine Antagonists / Q000494:pharmacology*; D006943:Hyperglycemia / Q000139:chemically induced / Q000188:drug therapy* / Q000517:prevention & control; D007276:Injections, Intraventricular; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D009388:Neostigmine / Q000037:antagonists & inhibitors*; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects* / Q000502:physiology
D006633:Histamine Antagonists; D011963:Receptors, GABA-A; D009118:Muscimol; D009388:Neostigmine; D006632:Histamine; D001418:Baclofen