Electrophysiological techniques were used to obtain recordings of extracellular electrical activity from the anterior end of live adult females of Brugia pahangi. Stimulation with 100mM, 10mM and 1mM acetylcholine resulted in an increase in spike activity which was concentration dependent, whereas stimulation with phosphate-buffered saline and 0·1mM acetylcholine gave no increase in activity. The delay in response was not concentration dependent. The action of possible host cues was investigated. Stimulation with heat-inactivated foetal calf serum (IFCS) and 10mM glutathione gave an increase in spike activity but exposure to 5mg/dl haemoglobin elicited no response. The response to IFCS was found to be suppressed completely by pre-incubation for 30min in ivermectin.
