“School of Cognitive”

Back to Papers Home
Back to Papers of School of Cognitive

Paper   IPM / Cognitive / 7914
School of Cognitive Sciences
  Title:   Dorsal hippocampal muscarinic and nicotinic receptors are involved in mediating morphine reward
  Author(s): 
1.  A. Rezayof
2.  H. Zatali
3.  A. Haeri-Rohani
4.  M.R. Zarrindast
  Status:   Published
  Journal: BEHAV BRAIN RES
  Vol.:  166
  Year:  2006
  Pages:   281-290
  Supported by:  IPM
  Abstract:
In the present study, the effects of bilateral injections of cholinergic agents into the hippocampal CA1 region on morphine-induced conditioned place preference (CPP) were investigated in male Wistar rats. Subcutaneous (s.c.) administration of different doses of morphine sulphate (0.5-6mg/kg) produced a dose-dependent CPP. Using a 3-day schedule of conditioning, it was found that intra-CA1 administration of the anticholinestrase, physostigmine (2, 4 and 8mug/rat) significantly potentiated the morphine (0.5mg/kg)-induced CPP. Moreover, intra-CA1 administration of the muscarinic receptor antagonist, atropine (1, 4 and 7mug/rat) inhibited the morphine (6mg/kg)-induced CPP dose-dependently. On the other hand, atropine (7mug/rat, intra-CA1) reversed the physostigmine-induced potentiation of the morphine response. Furthermore, intra-CA1 administration of nicotine (0.5, 0.75 and 1mug/rat) with an ineffective dose of morphine (0.5mg/kg) elicited a significant CPP. Bilateral injections of different doses of the nicotinic receptor antagonist, mecamylamine (2, 4 and 8mug/rat) into the CA1 regions significantly inhibited the morphine (6mg/kg)-induced CPP. Moreover mecamylamine (8mug/rat, intra-CA1) decreased the effect of nicotine-induced potentiation of the morphine response. Intra-CA1 injections of physostigmine, atropine, nicotine or mecamylamine alone did not induce a significant place preference or place aversion. It may be concluded that the muscarinic and nicotinic receptors of the hippocampal CA1 regions play an important role in morphine reward.

Download TeX format
back to top
scroll left or right