Persistent exercise attenuates nicotine- but not clonidine-induced antinociception in female rats.
Exercise decreases the antinociceptive effects of opiate drugs. It has been hypothesized that the exercise-induced attenuation of opiate drug action is the result of the development of cross-tolerance between endogenous opioids released during exercise and exogenous opiates. The present study was designed to evaluate the role of exercise on non-opiate antinociception. Female Long-Evans rats were allowed ad lib access to running wheels. After 3 weeks, antinociceptive responses of animals were measured using the tail flick test following the administration of clonidine or nicotine. Nicotine and clonidine both produced dose-dependent increases in antinociceptive responses. Active animals were significantly less sensitive to nicotine-induced antinociception than inactive animals. There was no difference between the two groups in clonidine-induced antinociception. The results of these experiments suggest that exercise does not attenuate non-opioid, clonidine-induced antinociception. However, exercise does attenuate nicotine-induced antinociception. Therefore, the effect of persistent exercise on analgesic drugs is not specific to opiates.
Mathes
Wendy Foulds
WF
Department of Psychology, Tufts University, 490 Boston Avenue, Medford, MA 02155, USA.
Kanarek
Robin B
RB
D000698:Analgesia; D000700:Analgesics / Q000494:pharmacology*; D000818:Animals; D003000:Clonidine / Q000494:pharmacology*; D004361:Drug Tolerance; D005260:Female; D009538:Nicotine / Q000494:pharmacology*; D018722:Nicotinic Agonists / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D010805:Physical Conditioning, Animal / Q000523:psychology*; D051381:Rats; D020318:Rats, Long-Evans; D011978:Receptors, Nicotinic / Q000187:drug effects
D000700:Analgesics; D018722:Nicotinic Agonists; D011978:Receptors, Nicotinic; C403531:nicotinic receptor alpha4beta2; D009538:Nicotine; D003000:Clonidine