Cortical alpha 1-adrenergic regulation of acute and sensitized morphine locomotor effects.
The role of alpha1-adrenergic transmission was tested on locomotor effects of acute or repeated morphine (5 mg/kg, i.p.) administration. Prazosin, an alpha1-adrenergic antagonist, administered 30 min before morphine, either systemically (0.5 mg/kg, i.p.) or locally and bilaterally into the prefrontal cortex (200 pmol/side) reduced the stimulatory influence of morphine on locomotion. The progressive increase of the locomotor response induced by repeated morphine injections was blocked by a prazosin pretreatment but not the behavioral sensitization on the test day. These data suggest that blockade of cortical alpha1-adrenergic receptors reduces the expression of acute and sensitized locomotor responses to morphine, but does not prevent the induction of behavioral sensitization.
Drouin
C
C
Inserm U.114, Collège de France, 11, Place Marcelin Berthelot, 75231 Paris Cedex 05, France.
Blanc
G
G
Trovero
F
F
Glowinski
J
J
Tassin
J P
JP
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000008:administration & dosage*; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects* / Q000502:physiology; D004334:Drug Administration Schedule; D007274:Injections, Intraperitoneal; D007276:Injections, Intraventricular; D008297:Male; D009020:Morphine / Q000008:administration & dosage*; D009043:Motor Activity / Q000187:drug effects* / Q000502:physiology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000502:physiology*
D058668:Adrenergic alpha-1 Receptor Antagonists; D000317:Adrenergic alpha-Antagonists; D000701:Analgesics, Opioid; D018340:Receptors, Adrenergic, alpha-1; D009020:Morphine; D011224:Prazosin