The Nervous Systems of Helminths as Targets for Drugs

Abstract

Processes that critically differentiate parasitic helminths and their hosts are obvious candidates for chemotherapeutic intervention. The recognition that neurobiology distinguishes helminths from their vertebrate hosts is due in part to the fact that several efficacious anthelmintics, derived generally from empirical screening, have been found to act selectively on the neuromuscular system of these parasites. In addition, basic physiological and pharmacological research has revealed considerable differences in the ways in which helminths and their hosts transmit information in the nervous system and respond to it in innervated tissues. Unfortunately, most of these differences have yet to be exploited in chemotherapy. The topics for this review include an analysis of mechanistic aspects of the pharmacology of anthelmintics that act on neuromuscular systems and a consideration of the prospects for discovery of novel drugs that act on this system.

In vitro studies on the relative sensitivity to ivermectin of Necator americanus and Ancylostoma ceylanicum

“…The experiments reported here used concentrations 2 1 PM, which have been previously criticized as being unrepresentatively high compared to effective in vivo concentrations (Geary, Klein, Vanover, Bowman & Thompson, 1992;Geary, Sims, Thomas, Vanover, Davis, Winterrowd, Klein, Ho & Thompson, 1993). The difference in sensitivity between the two species in vitro is also relatively lower than the difference in sensitivity shown in vivo (A. ceylanicum 4&50 times more sensitive than N. americanus in vitro, compared to a 20s300-fold difference in vivo).…”

Anthelmintic and cytotoxic activities of extracts of Markhamia obtusifolia Sprague (Bignoniaceae)

“…In the current study, water extracts were evaluated for cytotoxic activities in order to rule out cytotoxicity as the mechanism of action of M. obtusifolia extracts. Chemotherapeutic drugs against helminth infection act mainly through three different mechanisms, namely disruption of the neuromuscular physiology, blocking the energy metabolism, or disrupting the highly efficient reproductive system of the parasites (Geary et al, 1992). The results obtained in the current study indicate relatively lower levels of cytotoxicity compared to berberine.…”

Insect Toxicity and Repellent Activity of Phytochemicals from “Flea killer, Boenninghausenia albiflora” against “Black Garden Ant, Lasius Niger” of Pakistan

“…The known target sites on parasites are solely proteins and include ion channels, enzymes, structural proteins, transport molecules, etc. [18][19][20][21][22]. Sonia et al determined effect of Anthumgraveolens L. extract on biochemical and histopathological alteration of deltamethrin in rats [23].…”