The effects of isolation, grouping and aggressive interactions on indole- and catecholamine levels and apparent turnover in the hypothalamus and midbrain of the male golden hamster.
Although the golden hamster is widely used for studies on aggression, there have been no previous investigations of the role of biogenic amines in this species. Like the mouse, isolated male hamsters are highly aggressive towards a conspecific while grouped males are relatively unaggressive. Isolated males exhibited no differences in levels of midbrain or hypothalamic serotonin (5HT), 5-hydroxyindole acetic acid (5HIAA) or norepinephrine (NE) compared with grouped males. Nor were there differences in the percentage changes in 5HT or 5HIAA following monoamine oxidase inhibition by pargyline, nor in the percentage fall in hypothalamic NE after tyrosine hydroxylase inhibition by alpha-methyl-p-tyrosine (AMPT); midbrain NE in isolates (unlike grouped males) did not decline after AMPT administration. The percentage changes in 5HT after pargyline administration were unaffected by fighting, but the expected percentage fall in hypothalamic 5HIAA did not occur in males (either grouped or isolated) taking part in an aggressive interaction; this may be an indication of increased 5HT turnover. The percentage change in NE after AMPT administration was unaffected by fighting. Pargyline administration (70 mg/kg IP) reduced the aggressive response of isolated male hamsters to an intruder while AMPT (200 mg/kg IP) had no significant effect.
Payne
A P
AP
Andrews
M J
MJ
Wilson
C A
CA
D000374:Aggression / Q000502:physiology*; D000818:Animals; D001921:Brain / Q000378:metabolism*; D006224:Cricetinae; D006897:Hydroxyindoleacetic Acid / Q000032:analysis; D007031:Hypothalamus / Q000378:metabolism; D007211:Indoles / Q000378:metabolism*; D008297:Male; D008636:Mesencephalon / Q000378:metabolism; D008647:Mesocricetus; D009638:Norepinephrine / Q000378:metabolism*; D010293:Pargyline / Q000494:pharmacology; D012701:Serotonin / Q000032:analysis; D012934:Social Isolation
D007211:Indoles; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D010293:Pargyline; D009638:Norepinephrine