Nigrostriatal dopamine release modulated by mesopontine muscarinic receptors.
The present study investigated the regulation of substantia nigra pars compacta (SNc) dopamine neuronal activity by pedunculopontine (PPT) cholinergic neurons. Changes in dopamine efflux following chemical activation or blockade of muscarinic acetylcholine receptors in the PPT were measured at stearate-carbon paste electrodes in the striatum of urethane (1.5 g/kg) anaesthetized male rats using in vivo chronoamperometry (30 s sampling rate). Intra-PPT infusions of a mixed muscarinic/nicotinic (carbachol 8 microg/microl) or M2/4-selective muscarinic (oxotremorine 0.5 microg/microl) receptor agonist attenuated striatal dopamine efflux, whereas a non-selective (scopolamine 100 microg/microl) or M2/4-selective (methoctramine 50 microg/microl) muscarinic receptor antagonist enhanced striatal dopamine efflux. These results suggest that M2/4 muscarinic receptors in the mesopontine tonically influence SNc basal dopamine cell activity and striatal dopamine release.
Miller
Anthony D
AD
Department of Psychology, Macquarie University, Sydney, NSW 2109, Australia.
Blaha
Charles D
CD
D000818:Animals; D018679:Cholinergic Agonists / Q000494:pharmacology; D018680:Cholinergic Antagonists / Q000494:pharmacology; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D004298:Dopamine / Q000378:metabolism*; D008297:Male; D011149:Pons / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D011976:Receptors, Muscarinic / Q000378:metabolism*; D013378:Substantia Nigra / Q000187:drug effects / Q000378:metabolism*
D018679:Cholinergic Agonists; D018680:Cholinergic Antagonists; D011976:Receptors, Muscarinic; D004298:Dopamine