Pharmacological effect on scals of Rasbora elenga

Abstract

In the present study it is observed that the histamine perse caused dose dependent significant aggregating effects in the dorsal skin melanophores of Rasbora elenga. Higher concentrations of histamine caused more sever aggregating effects of the scale melanophores.The isolated scale melanophores of fish R.elanga maintained an intermediate state in physiological solution of 0.7 % NaCl. After this, melanophores are pretreated with a specific H3 Receptor antagonist thioperamide in the concentration of 2×10-6 g/ml. They were later incubated in increasing concentrations of histamine in a logarithmic scale of 1×10-6 g/ml to 6.4×10-5 g /ml. In the lowest concentration of 1×10-6 g/ml of histamine it was observed that thioperamide blocked the melanophore aggregation effect of histamine per se. Increase in the concentration of histamine with the blocker thioperamide to 3.2×10-5 g /ml the teleost melanophores were not able to aggregate in the presence of the antagonist. After that the melanophores of R.elenga were previously bathed in 0.7% Saline in order to bring the melanophores in the neutral state, where melanophores remained in a state of neither aggregation nor dispersion. When such scale melanophores were incubated with H3 Agonist immethridine it was observed that immethridine induced physiologically significant melanophore aggregation in all concentration. The intial concentration of immethridine perse of 1×10-6 g/ml caused the melanophores to decrease in size showing aggregation. Increase in the dose concentration of immethridine perse to 6.4×10-5 g /ml, induced a complete aggregation of all the melanophores