In vivo Effects of the Anatoxin-a on Striatal Dopamine Release

Anatoxin-a is an important neurotoxin that acts a potent nicotinic acetylcholine receptor agonist. This characteristic makes anatoxin-a an important tool for the study of nicotinic receptors. Anatoxin-a has been used extensively in vitro experiments, however anatoxin-a has never been studied by in vivo microdialysis studies. This study test the effect of anatoxin-a on striatal in vivo dopamine release by microdialysis.The results of this work show that anatoxin-a evoked dopamine release in a concentration-dependent way. Atropine had not any effect on dopamine release evoked by 3.5 mM anatoxin-a. However, perfusion of nicotinic antagonists mecamylamine and α-bungarotoxin induced a total inhibition of the striatal dopamine release. Perfusion of α7*-receptors antagonists, metillycaconitine or α-bungarotoxin, partially inhibits the release of dopamine stimulated by anatoxin-a. These results show that anatoxin-a can be used as an important nicotinic agonist in the study of nicotinic receptor by in vivo microdialysis technique and also support further in vivo evidences that α7*nicotinic AChRs are implicated in the regulation of striatal dopamine release.