Acoustic Stimulation Acoustics Animals Biphenyl Compounds Dose-Response Relationship, Drug Electric Stimulation Evoked Potentials, Auditory Excitatory Postsynaptic Potentials Female Goldfish Guanidines Inhibitory Postsynaptic Potentials Male Mauthner cell N (2,6 dimethoxybenzyl) N' (4 (4 fluorophenyl)thiazol 2 yl)guanidine N-(2,6-dimethoxybenzyl)-N'-(4-(4-fluorophenyl)thiazol-2-yl)guanidine Nerve Net Neural Inhibition Neural Pathways Neurons Patch-Clamp Techniques Potassium Chloride Receptors, Serotonin SB 699551 A SB-699551-A Sensory Gating Serotonin Antagonists Spinal Cord Startle Reaction Thiazoles