Responses of Olanzapine as an Antagonist to 5-Hydroxytryptamine on Isolated Scale of Melanophores of Rasbora daniconius (Ham.)

Responses of Olanzapine, a specific 5-HT₄ receptor antagonist,were studied in dorso-lateral region as well as in band region melanophores of Rasbora daniconius. The melanophore size index (MSI) was considered as a parameter for studying responses. Olanzapine (1.6 x 10^-5M), the specific 5-HT₄ receptor antagonist, strongly inhibited the aggregator effect of 5-HT, which provided a strong evidence for the presence of 5-HT₄ receptor in Rasbora daniconius melanophores.