H. Klemfuss et Jc. Gillin, NEONATAL SCOPOLAMINE OR ANTIDEPRESSANT TREATMENT - EFFECT ON DEVELOPMENT OF HAMSTER CIRCADIAN-RHYTHMS, Pharmacology, biochemistry and behavior, 59(2), 1998, pp. 369-373
Chronic treatment of young rodents with drugs altering monoamine metab
olism has been reported to produce lasting effects on behavior that re
semble human affective disorders. To test the generality of this findi
ng, scopolamine, imipramine, or clomipramine was injected daily betwee
n the ages of 8 and 21 days in golden hamsters, Wheel-running rhythms
were monitored continuously from the age of 4 to 20 weeks of age to te
st the hypothesis that neonatal treatments would lower the amplitude o
f biological activity rhythms in adults. Of these three neonatal treat
ments only scopolamine altered running rhythms, significantly increasi
ng the amplitude of running rhythms in adult hamsters under both entra
ined and free-running conditions. Hamsters treated neonatally with sco
polamine were also more sensitive to the hypothermic effects of the mu
scarinic agonist, oxotremorine, as adults. These data indicate that ne
onatal exposure to cholinergic receptor blockade may produce long-last
ing changes in biological rhythm characteristics related to upregulati
on of muscarinic receptors. (C) 1998 Elsevier Science Inc.