The modulatory effect of pyrethroids on acetylcholine release in the hippocampus of freely moving rats.
The peripheral effects of pyrethroids on Na(+) channels are well known but the effects on CNS neurotransmission are less known. In the present study, type I and II pyrethroids were found to affect the release of acetylcholine (ACh) from hippocampus in freely moving rats as measured by in vivo microdialysis. The basal release of ACh from the hippocampus of untreated rats was 6.6 pmol/10 microl/10 min. Allethrin had an interesting dual effect on ACh release, increasing ACh efflux (to about 300% of baseline) at the lower dose of 20 mg/kg i.p. with a peak time of 60 min and decreasing the efflux (to about 40% of baseline) at the higher dose of 60 mg/kg i.p. up to 3 h after administration. Cyhalothrin 20 and 60 mg/kg i.p. inhibited the release (to about 30% of baseline) dose-dependently, with a peak time of 50-60 min after administration. Deltamethrin 20 mg/kg i.p. increased the efflux (to about 250% of baseline) with a peak time of 30 min after administration and 60 mg/kg i.p. increased the efflux (to about 450% of baseline) and remained at a steady level during the rest of the 3 h experiment. Control vehicle injections had no effect on the efflux of ACh in any of the experiments. This is the first report, using in vivo microdialysis, that pyrethroids modulate the ACh release in the hippocampus of rat brain.
Department of Veterinary Medicine, Faculty of Agriculture, Iwate University, Morioka 020-8550, Japan. g0102201@iwate-u.ac.jp
Muhammad Mubarak
MM
Hossain
Tadahiko
T
Suzuki
Itaru
I
Sato
Tadashi
T
Takewaki
Koichi
K
Suzuki
Haruo
H
Kobayashi
D000109:Acetylcholine / Q000378:metabolism*; D000110:Acetylcholinesterase / Q000378:metabolism; D000487:Allethrins / Q000633:toxicity; D000818:Animals; D002404:Catheterization; D002794:Choline / Q000378:metabolism; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D007306:Insecticides / Q000494:pharmacology*; D008297:Male; D017551:Microdialysis; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009570:Nitriles; D011722:Pyrethrins / Q000494:pharmacology* / Q000633:toxicity; D051381:Rats; D017207:Rats, Sprague-Dawley
D000487:Allethrins; D007306:Insecticides; D009419:Nerve Tissue Proteins; D009570:Nitriles; D011722:Pyrethrins; C017180:decamethrin; D002795:Choline O-Acetyltransferase; D000110:Acetylcholinesterase; D002794:Choline; D000109:Acetylcholine; C037304:cyhalothrin