ABSTRACTVarious catecholamines and catecholamine antagonists have been examined for their effects on the third larval moult of the parasitic nematode, Dirofilaria immitis, cultured in vitro. The non-selective α and β agonist, noradrenaline, and the β agonist, isoprenaline, had no effect on the timing of the third stage moult when used at a concentration of 10−5M. The α-adrenergic antagonist. phentolamine, resulted in worm mortality at 10−5M. At 10−7M, both phentolamine and the β-antagonist, propranolol caused a significant reduction in the numbers of larvae capable of completing the third stage moult. Idazoxan, an a2-antagonist, at 10−5M did not affect worm mortality but did completely prevent ecdysis. The potential of these compounds as possible filaricides is discussed.
Angiostrongylus cantonensis (Nematode: Metastrongiloidea): In Vitro Cultivation of Infective Third-Stage Larvae to Fourth-Stage Larvae