INTRODUCTION Serotonin is a monoamine neurotransmitter derived biochemically from L-tryptophan. It is mainly found in the gastrointestinal tract (about 90% in enterochromaffin cells), platelets and in the central nervous system of humans and animals. It is an important biogenic amine that play combined role of neurotransmitter as well as neuromodulator (Gyermek, 1996). Serotonin, a neurotransmitter synthesized in the brain, acts importantly in the functioning of the cardiovascular, renal,...
