Increased plasma corticosterone, aggressiveness and brain monoamine changes induced by central injection of pertussis toxin.
The effects of intracerebroventricular (i.c.v.) injection of pertussis toxin, a specific inhibitor of G(i)/G(o) proteins, on plasma corticosterone levels, aggressiveness, and hypothalamic and hippocampal monoamines and their metabolites levels were examined in mice. Plasma corticosterone level was markedly increased at 3 h after pertussis toxin injection (0.03 and 0.2 microg/mouse), peaked at 6 h and was still increased for up to 6 days after injection. Mice injected with pertussis toxin (0.2 microg/mouse) did not show weight gain between day 0 and day 6 after injection. In addition, pertussis toxin (0.2 microg/mouse) induced a progressive increase in aggressiveness, i.e. a decrease in attack latency and an increase in number of attacks, on day 1 and 6 after injection. Brain monoamines and their metabolites levels were changed on day 1 and 6 after pertussis toxin injection (0.2 microg/mouse): in the hypothalamus, levels of dopamine and 3,4-dihydroxyphenylacetic acid were increased, norepinephrine level decreased, and 5-hydroxyindole acetic acid (5-HIAA) level was markedly increased, with no changes in 5-hydroxytryptamine (5-HT) level, whereas in the hippocampus, 5-HT level was significantly decreased, with no changes in 5-HIAA and catecholamines. These results suggest that signal transduction through G(i)/G(o) proteins in the brain is involved in the modulation of hypothalamo-pituitary-adrenal axis, aggressiveness, and monoamine levels in vivo.
Kim
D H
DH
Department of Psychiatry, College of Medicine, Institute of Natural Medicine, Hallym University, Kangwon, 200-702, Chunchon, South Korea.
Jung
J S
JS
Yan
J J
JJ
Suh
H W
HW
Son
B K
BK
Kim
Y H
YH
Song
D K
DK
D000374:Aggression / Q000187:drug effects*; D000818:Animals; D015306:Biogenic Monoamines / Q000378:metabolism*; D001923:Brain Chemistry / Q000187:drug effects*; D003345:Corticosterone / Q000097:blood*; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D037342:Pertussis Toxin; D010566:Virulence Factors, Bordetella / Q000008:administration & dosage / Q000494:pharmacology*
D015306:Biogenic Monoamines; D010566:Virulence Factors, Bordetella; D037342:Pertussis Toxin; D003345:Corticosterone