Neuropharmacology of rotifer feeding, oviposition, and anesthesia

Abstract of Communication

Effect of acetylcholine and anticholinergic drugs on feeding, oviposition, and anesthesia in rotifers was investigated. Neurotransmitter as well as antagonist drugs inhibited feeding in Brachionus calyciflorusin a dose-dependent manner. Most antagonist drugs caused an oscillating tachyphylaxis (drug habituation): the drug effect wore off and returned several times within an hour. Acetylcholine inhibited oviposition in Philodina acuticornis, and this effect was antagonized by all groups of anticholinergic drugs. The strongest antagonism was caused by neuromuscular blockers, and thus the cause of oviposition inhibition may be a cloaca1 sphincter spasm. Acetylcholinesterase inhibitory insecticides also antagonize the acetylcholine effect. Acetylcholine potentiates the anesthetic activity of ionizing local anesthetics (procaine, lidocaine) as well as that of atropine and the beta-adrenergic blocker propranolol. Muscarinic antagonists (atropine, benactyzine) and propranolol caused foot paralysis in B. calyciforus, which is also potentiated by acetycholine. Further details of these results are given by Nogrady and Keshmirian (1986a, b).