GABAB receptors within the ventral tegmental area are involved in the expression and acquisition of morphine-induced place preference in morphine-sensitized rats.
The influence of intra-ventral tegmental area administration of gamma-amino-butyric-acid-B (GABAB) receptor agonist and antagonist on the expression and acquisition of morphine-induced conditioned place preference (CPP) in morphine-sensitized female rats was examined. Our pilot experiment showed that subcutaneous administration of morphine-(2.5, 5 and 7.5 mg/kg) induced CPP. Administration of one dose daily morphine (5 mg/kg) for 3 days followed by 5 days rest, enhanced the conditioning induced by ineffective doses of morphine (0.25, 0.5 and 1 mg/kg). Injections of GABAB receptor agonist, baclofen, (1.5 and 12 microg/rat) reduced the expression of morphine CPP whereas the dose of 6 microg/rat of the drug increased it. Baclofen also significantly reduced the acquisition of morphine CPP in morphine-sensitized animals. Administration of GABAB receptor antagonist, CGP 35348, significantly reduced the expression (12 microg/rat) and acquisition (1.5, 6 and 12 microg/rat) of morphine CPP in morphine-sensitized animals. In conclusion, results confirmed the importance of GABAB receptors within the ventral tegmental area of morphine CPP in morphine-sensitized female rats.
Sahraei
Hedayat
H
Department of Physiology and Biophysics and Applied Neuroscience Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran. h.sahraei@bmsu.ac.ir
Etemadi
Leila
L
Rostami
Parvin
P
Pourmotabbed
Ali
A
Zarrindast
Mohammad-Reza
MR
Shams
Jamal
J
Ghoshooni
Hassan
H
Noroozzadeh
Ali
A
Esfandiari
Behnaz
B
Salimi
Seyed Hossein
SH
D000818:Animals; D001418:Baclofen / Q000494:pharmacology; D003216:Conditioning, Operant / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D018755:GABA Agonists / Q000494:pharmacology; D018756:GABA Antagonists / Q000494:pharmacology; D008845:Microinjections; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects; D009294:Narcotics / Q000008:administration & dosage / Q000494:pharmacology*; D009943:Organophosphorus Compounds / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D011963:Receptors, GABA-A / Q000187:drug effects / Q000502:physiology*; D018080:Receptors, GABA-B / Q000187:drug effects; D012054:Reinforcement, Psychology; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology*
D018755:GABA Agonists; D018756:GABA Antagonists; D009294:Narcotics; D009943:Organophosphorus Compounds; D011963:Receptors, GABA-A; D018080:Receptors, GABA-B; D009020:Morphine; C066430:CGP 35348; D001418:Baclofen