title: Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia.
abstract: Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia. Experimental Parasitology 97, 9-14. Giardia infection is predominant in the small intestine of vertebrates, where the trophozoites attach to epithelial cells and adversely affect the microvilli and other epithelial cell structures. Giardiasis, the disease caused by this protozoan, is very common in developing countries and mainly affects children. Drugs currently used to treat Giardia infection, such as some benzimidazole derivatives, were originally designed to treat helminthic infections. Many of the drugs are known to cause severe side effects and disturbances to the patient. Using transmission electron microscopy and video-light microscopy, we studied the effects of pyrantel pamoate, a drug commonly used in the treatment of helminthic infections in horses and ruminants, on Giardia lamblia trophozoites. Pyrantel pamoate was administered to Giardia cells in four different concentrations. Using video-light microscopy, we observed the decrease in flagella beating frequency and severe changes in the lateral flange and in the general aspect of the cell. Using transmission electron microscopy, we observed changes in the cytoplasm and peripheral vesicles. The flagella and adhesive disk structure were not affected. Apparently, the effects of pyrantel pamoate are irreversible.
authors.affiliation: Department of Histology and Embryology, Laboratory of Microscopy and Image Processing, State University of Rio de Janeiro, Av. Prof. Manoel de Abreu, 48 3 degrees andar, Maracanã, Rio de Janeiro, CEP 20550-170, Brazil.
authors.forename: L
authors.initials: L
authors.lastname: Campanati
authors.forename: A P
authors.initials: AP
authors.lastname: Gadelha
authors.forename: L H
authors.initials: LH
authors.lastname: Monteiro-Leal
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000008:administration & dosage / Q000494:pharmacology*; D003470:Culture Media; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005407:Flagella / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D016829:Giardia lamblia / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D018715:Microscopy, Video; D011716:Pyrantel Pamoate / Q000008:administration & dosage / Q000494:pharmacology*; D012997:Solvents / Q000494:pharmacology
chemical_list: D000981:Antiprotozoal Agents; D003470:Culture Media; D012997:Solvents; D011716:Pyrantel Pamoate; D004121:Dimethyl Sulfoxide