The neuropharmacological studies of Paramphistomum cervi were conducted ex vivo by extracellular electrical activity. The instrumentation and methodology described in the experiment, quantitatively measure the extracellular electrical potentials associated with motor activity and provide highly sensitive objective techniques for studying the effects of antitrematodal compounds and for evaluating P. cervi as a model for neuropharmacological investigations. In the present investigation, the effects of various neuropharmacological agents viz. amino acid neurotransmitters [l-glutamate, gamma-amino butyric acid (GABA), glycine], GABA antagonists (picrotoxin and bicuculline) and glycine antagonist (strychnine) were investigated on the spontaneous muscular activity of P. cervi. l-Glutamate, an excitatory neurotransmitter produced significant increase in amplitude and baseline tension at 10−7–10−5 M concentration, and frequency at 10−4–10−3 M concentration. Glycine, an inhibitory neurotransmitter on the other hand, produced significant reduction of amplitude at 10−6–10−3 M concentration and baseline tension and frequency at 10−3 M concentration. On the contrary, strychnine an antagonist of glycine produced significant increase of amplitude, baseline tension and frequency at 10−6–10−3 M concentration. Another inhibitory neurotransmitter, GABA mediated significant reduction in amplitude and baseline tension at 10−3 M concentration. Picrotoxin, being an antagonist of GABA produced marked significant increase in amplitude (g) and baseline tension (g) at 10−7–10−3 M concentration with an increase in frequency at 10−4 and 10−3 M concentration. In the present study another GABAA antagonist, bicuculline was found to be non responsive in P. cervi.