Morphine withdrawal and schedule-induced polydipsia.
Schedule-induced polydipsia (SIP) is the characterized behavior for reducing the heightened arousal in a schedule of intermittent feeding. In the present study, SIP rats received an incremental doses of morphine in repeated treatments on the first 5 days and were then challenged by naloxone on the 6th day. We examined the SIP performance during morphine dependence and withdrawal. The roles of the locus coeruleus (LC) and excitatory amino acid (EAA) pathways were examined by bilateral LC lesions and lateral ventricle kynurenic acid infusion. In each manipulation, the level of water intake was recorded as an index of SIP strength. Our results showed that morphine dependence reduced SIP strength, whereas withdrawal initially reduced but then elevated SIP strength. Such effects were attenuated by bilateral LC lesions or kynurenic acid administration. The implications of these results on morphine withdrawal reaction and SIP performance were discussed.
Liu
Y P
YP
Military 818 Psychiatry Hospital, Taipei, Taiwan, ROC.
Chiang
C P
CP
Tseng
C J
CJ
Huang
N K
NK
Yin
T H
TH
Tung
C S
CS
D000818:Animals; D004327:Drinking Behavior / Q000187:drug effects / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D007276:Injections, Intraventricular; D007736:Kynurenic Acid / Q000494:pharmacology; D008125:Locus Coeruleus / Q000502:physiology; D008297:Male; D009020:Morphine / Q000009:adverse effects*; D009021:Morphine Dependence / Q000523:psychology; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012965:Sodium Chloride / Q000494:pharmacology; D013375:Substance Withdrawal Syndrome
D009292:Narcotic Antagonists; D009270:Naloxone; D012965:Sodium Chloride; D009020:Morphine; D007736:Kynurenic Acid