Immunohistochemistry and nerve lesion experiments on the methionine-enkephalin immunopositive neurons in the small intestine of the bullfrog (Rana catesbeiana).
Nerve elements in the small intestine of the bullfrog. Rana catesbeiana, were studied by immunohistochemistry with anti-methionine enkephalin antisera and by nerve lesion experiments, using laser irradiation. Methionine-enkephalin immunopositive nerve fibers occur in the myenteric plexus, circular muscle layer, submucosa, and mucosa. Immunopositive nerve cell bodies in the myenteric plexus have dendrite-like and a long axon-like processes. In the froglet (3 months after metamorphosis), these axon-like processes lead posteriorly in the nerve strand of the myenteric plexus. Some bifurcate, one branch continuing posteriorly, the other doubling back to lead anteriorly; both form terminal varicose fibers in the circular muscle layer. Nerve lesion experiments, in the adult bullfrog, resulted in accumulations of methionine-enkephalin immunoreactivity at the oral and hinder edges of the laser-irradiated necrotic area; there were sprouting and nonsprouting immunopositive stumps. It is suggested that bidirectional flow of methionine-enkephalin in the myenteric plexus is mediated via the anterior and posterior branches of the axon-like process. The difference in sprouting behavior of immunopositive nerve fiber stumps, after nerve lesion, is discussed with reference to regional differences of the axon-like process.
Torihashi
S
S
Department of Anatomy, Yamanashi Medical College, Japan.
Kobayashi
S
S
D000818:Animals; D004744:Enkephalin, Methionine / Q000378:metabolism*; D005260:Female; D007150:Immunohistochemistry; D007413:Intestinal Mucosa / Q000294:innervation; D007421:Intestine, Small / Q000294:innervation*; D007834:Lasers; D008297:Male; D008643:Mesentery / Q000294:innervation; D008675:Metamorphosis, Biological; D009130:Muscle, Smooth / Q000294:innervation; D009197:Myenteric Plexus / Q000378:metabolism; D009412:Nerve Fibers / Q000378:metabolism / Q000528:radiation effects; D009474:Neurons / Q000378:metabolism* / Q000528:radiation effects; D011892:Rana catesbeiana / Q000033:anatomy & histology / Q000254:growth & development / Q000378:metabolism*
D004744:Enkephalin, Methionine