Mb. Dwinell et al., PRAZIQUANTEL TREATMENT NORMALIZES INTESTINAL MYOELECTRIC ALTERATIONS ASSOCIATED WITH HYMENOLEPIS DIMINUTA-INFECTED RATS, The Journal of parasitology, 81(6), 1995, pp. 979-984
Hymenolepis diminuta-associated alterations in rat intestinal myoelect
ric patterns are abolished following therapeutic administration of the
anthelmintic praziquantel (PZQ). Host intestinal smooth muscle myoele
ctric patterns, reflecting smooth muscle contractility and intestinal
phasic motility, were recorded using in vivo serosal electrodes, surgi
cally implanted on the duodenum, jejunum, and ileum. Repeated electrom
yographic recording from unrestrained and unanesthetized rats began 5
days after electrode implantation surgery. Three initial control recor
dings from each rat confirmed the appearance of normal intestinal myoe
lectric patterns, characterized by the interdigestive migrating myoele
ctric complex (MMC). All animals were subsequently infected with H, di
minuta and myoelectric recordings beginning after day 8 postinfection
confirmed the appearance of diminished frequency of the MMC and 2 nonm
igrating myoelectric patterns, i.e., repetitive bursts of action poten
tials and sustained spike potentials. PZQ was used to remove the tapew
orms from rats 12 days after Hymenolepis diminuta infection, as intest
inal myoelectric changes become maximal at this time in tapeworm-infec
ted rats. PZQ administered to uninfected rats at either of 2 dose leve
ls did not affect host interdigestive myoelectric activity. After remo
val of the parasite with PZQ, electromyographic recordings indicated a
return to normal uninfected electrical patterns within 24 hr of drug
treatment. We have demonstrated that the presence of Hymenolepis dimin
uta is necessary to induce and maintain abnormal intestinal myoelectri
c patterns. The altered motor properties of tapeworm-infected rat inte
stine and the rapid reconversion to preinfection myoelectric patterns
provides a new and unique model to examine the regulatory mechanisms o
f intestinal motility and its control by luminal parasites.