Prenatal exposure to morphine alters analgesic responses and preference for sweet solutions in adult rats.
In the present study, we examined long-term effects of prenatal morphine on pain response and on preference for sweet solutions. Pregnant Fischer 344 rats were given increasing doses of morphine (0.75-12.0 mg/day) in slow-release emulsion, during gestational days 12-18. Control rats were injected with vehicle and were either pair-fed to morphine rats, or ad libitum fed. At birth, all litters were culled to 8-10 pups (half males and half females) and cross-fostered to naive, surrogate dams. Testing began when rats were 10-12 week old. Rats prenatally exposed to morphine exhibited higher analgesia in response to a morphine challenge, and a greater preference for saccharin solution as compared with both control groups. These findings indicate that prenatal morphine induces long-lasting alterations of systems involved in reward processes and in opiate analgesia, perhaps by modulating endogenous opiate systems.
Gagin
R
R
Department of Psychology, Hebrew University of Jerusalem, Israel.
Cohen
E
E
Shavit
Y
Y
D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D003692:Delayed-Action Preparations; D005260:Female; D005518:Food Preferences / Q000187:drug effects; D008297:Male; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects; D011247:Pregnancy; D011297:Prenatal Exposure Delayed Effects; D051381:Rats; D011916:Rats, Inbred F344; D011930:Reaction Time / Q000187:drug effects; D012439:Saccharin / Q000494:pharmacology*; D013549:Sweetening Agents / Q000494:pharmacology*; D013649:Taste / Q000187:drug effects*
D000701:Analgesics, Opioid; D003692:Delayed-Action Preparations; D013549:Sweetening Agents; D009020:Morphine; D012439:Saccharin