Inhibitory neurotransmission in lethal spotted mutant mice: a model for Hirschsprung's disease.
OBJECTIVE
The pathogenesis of Hirschsprung's disease is not well understood. The suitability of the animal model for the unknown pathogenesis of inhibitory neurotransmission in Hirschsprung's disease was investigated.


METHODS
Circular smooth muscle strips from the internal anal sphincter (IAS) and distal colon (2, 6, 8, 16, and 24 mm from the anal verge) from normal and Ls/Ls mice (mice homozygous for the lethal spotting mutation that develop fetal megacolon after aganglionosis of the terminal colon) were prepared to record changes in isometric tensions in response to different agents and nonadrenergic, noncholinergic nerve stimulation by electrical field stimulation.


RESULTS
Bethanechol was used to produce contraction of the smooth muscle strips of distal colon to record a decrease in the tension. Conversely, the IAS smooth muscle strips developed spontaneous tone. In the normal homozygous mice, electrical field stimulation caused a biphasic response, an initial decrease followed by an after-contraction, whereas in Ls/Ls mice, the predominant response was contraction. All smooth muscle strips from normal and Ls/Ls mice produced relaxation in response to sodium nitroprusside and vasoactive intestinal polypeptide.


CONCLUSIONS
Ls/Ls mice may serve as an appropriate animal model to investigate the pathogenesis of the inhibitory neurotransmission in Hirschsprung's disease in the distal colon and IAS.
Chakder
S
S
Department of Medicine, Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
McHugh
K M
KM
Rattan
S
S
D001003:Anal Canal / Q000187:drug effects / Q000503:physiopathology; D000818:Animals; D003106:Colon / Q000187:drug effects / Q000503:physiopathology; D004195:Disease Models, Animal; D004558:Electric Stimulation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006627:Hirschsprung Disease / Q000662:veterinary*; D051379:Mice; D008817:Mice, Mutant Strains; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology; D009130:Muscle, Smooth / Q000503:physiopathology; D009433:Neural Inhibition; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D012016:Reference Values; D012376:Rodent Diseases / Q000235:genetics / Q000503:physiopathology*; D009435:Synaptic Transmission; D014660:Vasoactive Intestinal Peptide / Q000037:antagonists & inhibitors / Q000494:pharmacology
D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D019335:Nitroarginine; D014660:Vasoactive Intestinal Peptide; D019001:Nitric Oxide Synthase