Effects of 24-hr fasting on methamphetamine- and apomorphine-induced locomotor activities, and on monoamine metabolism in mouse corpus striatum and nucleus accumbens.
The effects of 24-hr fasting on the vertical (VMA) and horizontal (HMA) locomotor activities, on cage climbing activity and on brain monoamine-related substances, were examined using male ddY mice. Both the VMA and HMA increased with fasting, but not the cage climbing activity. Methamphetamine (2 mg/kg, SC) increased the VMA and HMA in both the feeding and fasting mice, whereas with apomorphine (0.1 mg/kg, SC) both decreased. Furthermore, pretreatment with haloperidol (0.025 mg/kg, SC) showed no influence on the methamphetamine-induced VMA increase in both the feeding and fasting mice. However, pretreatment with haloperidol inhibited the methamphetamine-induced HMA increase in both the feeding and fasting mice and showed a higher level of HMA in fasting mice than in feeding mice. When measuring brain monoamine-related substances, the DA, NE, 5-HT, and 5-HIAA levels in the corpus striatum increased, whereas the 3-MT levels decreased. The monoamine levels in the nucleus accumbens of fasting mice were the same as those in feeding mice, except for a decrease of the 3-MT level. These results suggest that the locomotor activity in fasting mice may be increased by a change in the sensitivity of dopaminergic neurons in the corpus striatum.
Itoh
T
T
Department of Pharmacology, School of Dentistry, Iwate Medical University, Morioka, Japan.
Murai
S
S
Nagahama
H
H
Miyate
H
H
Abe
E
E
Fujiwara
H
H
Saito
Y
Y
D000818:Animals; D001058:Apomorphine / Q000494:pharmacology*; D015306:Biogenic Monoamines / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D003342:Corpus Striatum / Q000378:metabolism; D004347:Drug Interactions; D005215:Fasting / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051379:Mice; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D009714:Nucleus Accumbens / Q000378:metabolism
D015306:Biogenic Monoamines; D008694:Methamphetamine; D006220:Haloperidol; D001058:Apomorphine