In vitro effect of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on muscarinic cholinergic receptors in mouse striatum.
1. MPTP significantly lowered Kd of the binding of [3H]QNB to muscarine receptor without affecting Bmax values compared with those of control. Hill coefficients (nH) of control and MPTP (250 microM) added group were 1.15 +/- 0.127 and 0.56 +/- 0.202, respectively. 2. Prior addition of pargyline to MPTP did not prevent the decrease of [3H]QNB binding. The patterns of displacement of [3H]QNB by MPTP and MPP+ were similar to those by some muscarinic agonists, such as acetylcholine, carbamyl choline and methacholine. 3. These results suggest that MPTP might be muscarinic agonist and might play a role to produce Parkinsonism through directly affecting the muscarinic cholinergic receptors in vivo.
Suh
Y H
YH
Department of Pharmacology, College of Medicine, Seoul National University, Korea.
Cho
M
M
Woo
J I
JI
Park
C W
CW
D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects*; D066298:In Vitro Techniques; D020267:MPTP Poisoning; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D011813:Quinuclidinyl Benzilate / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000187:drug effects*
D011976:Receptors, Muscarinic; D011813:Quinuclidinyl Benzilate