Effects of p-chlorophenylalanine on striatal acetylcholinesterase activity and on biogenic amine levels in nuclei raphe and caudate-putamen during physostigmine-induced tremor in rats.
The biochemical mechanism underlying tremor is unknown. We investigated the effects of p-chlorophenylalanine (pCPA), a serotonin (5-HT) depletor, on the neurochemical processes in nuclei raphe dorsalis (NRD) and caudatus putamen (NCP) paralleling physostigmine-induced tremor in rats. Peak of physostigmine tremor correlated with increase in 5-HT in NRD and NCP, and a decrease in striatal dopamine (DA), as assayed employing high pressure liquid chromotography-electrochemistry. Administration of pCPA caused significant decrease in DA, norepinephrine (NE) and 5-HT levels in both the nuclei, without affecting striatal NE content and acetylcholinesterase activity. pCPA pretreatment significantly inhibited physostigmine-induced tremor and blocked corresponding increase in the levels of 5-HT in NRD and NCP. These results indicate involvement of central 5-HT, but not DA or NE, in the genesis of physostigmine tremor.
Mehta
H
H
Laboratory of Neurochemistry, Division of Pharmacology and Experimental Therapeutics, Indian Institute of Chemical Biology 4, Raja S. C. Mullick Road, Calcutta 700 032, India.
Thomas
B
B
Mohanakumar
K P
KP
D000110:Acetylcholinesterase / Q000187:drug effects* / Q000378:metabolism; D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism*; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism; D010134:Fenclonine / Q000494:pharmacology*; D017072:Neostriatum / Q000187:drug effects* / Q000201:enzymology; D009638:Norepinephrine / Q000378:metabolism; D010830:Physostigmine / Q000494:pharmacology; D011903:Raphe Nuclei / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012701:Serotonin / Q000378:metabolism; D012702:Serotonin Antagonists / Q000494:pharmacology*; D014202:Tremor / Q000139:chemically induced / Q000201:enzymology* / Q000503:physiopathology
D001679:Biogenic Amines; D002800:Cholinesterase Inhibitors; D012702:Serotonin Antagonists; D012701:Serotonin; D010830:Physostigmine; D000110:Acetylcholinesterase; D010134:Fenclonine; D004298:Dopamine; D009638:Norepinephrine