title: Angiostrongylus cantonensis: paralysis due to avermectin B1a and ivermectin.
abstract: Paralysis due to avermectin B1a and ivermectin of Angiostrongylus cantonensis was compared to that of phenylephrine (an alpha-adrenergic agonist) and strychnine (a cholinergic inhibitor). The paralyzing action of ivermectin (2.5 X 10(-9) g/ml) was inhibited by the single, simultaneous addition of picrotoxin (3 X 10(-5) M), whereas the effect of the drug (2.5 X 10(-7) g/ml) was reversed only when picrotoxin was given with cholinergic spasmogens such as pyrantel and eserine. Bicuculline (3 X 10(-5) M) had a similar antagonistic effect for picrotoxin, but bicuculline was less effective. The paralyzing action of avermectin B1a (3.6 X 10(-14) M, 3.0 X 10(-14) g/ml) was antagonized only when picrotoxin was given with cholinergic spasmogens such as pyrantel, eserine, and N-methylcytisine (N-MC), or alpha-adrenergic antagonists such as phentolamine and dibenamine. On the other hand, the paralyzing action of strychnine (3 X 10(-6) M) or phenylephrine (3 X 10(-5) M) was relatively uninfluenced by picrotoxin, but was antagonized by pyrantel and N-MC or dibenamine. These results suggest that a gabergic mechanism is involved in the paralyzing action of ivermectin, as well as avermectin B1a, in A. cantonensis.
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000470:Alkaloids / Q000494:pharmacology; D000801:Angiostrongylus / Q000187:drug effects* / Q000502:physiology; D000818:Animals; D000871:Anthelmintics / Q000494:pharmacology*; D001640:Bicuculline / Q000494:pharmacology; D007559:Ivermectin / Q000031:analogs & derivatives; D007783:Lactones / Q000494:pharmacology*; D008681:Metastrongyloidea / Q000187:drug effects*; D009068:Movement / Q000187:drug effects; D009119:Muscle Contraction / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology; D010830:Physostigmine / Q000494:pharmacology; D010852:Picrotoxin / Q000494:pharmacology; D011715:Pyrantel / Q000494:pharmacology; D011807:Quinolizines; D013331:Strychnine / Q000494:pharmacology; D000093843:Quinolizidine Alkaloids
chemical_list: D000317:Adrenergic alpha-Antagonists; D000470:Alkaloids; D000871:Anthelmintics; D001640:Bicuculline; D007559:Ivermectin; D007783:Lactones; D010656:Phenylephrine; D010830:Physostigmine; D010852:Picrotoxin; D011715:Pyrantel; D011807:Quinolizines; D013331:Strychnine; C022120:avermectin B(1)a; C034245:N-methylcytisine; D000093843:Quinolizidine Alkaloids