Distribution of Acetylcholinesterase in the Octavolateral Area of Heteropneustes fossilis

Abstract

Octavolateral area is a significant component of rhombencephalon in teleosts which shows a fine cytoarchitecture and comprises many intermingled nuclear groups. In the present study, distribution pattern of enzyme acetylcholinesterase has been carried out by employing a modified histochemical technique to visualize acetylcholine containing neurons described by Hedreen, J.C. et.al. (1985).
Acetylcholinesterase is an effective marker of cholinergic-cholinoceptive neurons since it hydrolyses acetylcholine in to choline and acetate at synaptic clefts. Present histochemical results exhibited a widespread distribution of acetylcholinesterase in the different nuclei of octavolateral area of Heteropneustes. Octavolateral efferent nucleus, medial octavolateral nucleus, magnocellular and posterior octaval nucleus demonstrated intense activity for acetylcholinesterase, while anterior octavolateral nucleus and descending octaval nucleusexhibited moderate staining. The distribution of acetylcholinesterase was homogenous in the whole rostro-caudal and lateral extension of this nucleus. hus in overall picture, octavolateral nucleus contains abundant cholinergic cells in the brai of Heteropneustes. In conclusion, the abundance of cholinergic innervations in this area is a well conserved characteristic among vertebrates which has been discussed from phylogenetic perspective.