Innervation of the pigeon oviduct: correlation of NADPH diaphorase with acetylcholinesterase, tyrosine hydroxylase, and neuropeptides.
The motility of the avian oviduct is controlled by hormones and neurons, but little is microscopically known about a neural network in the oviduct. The present study was investigated to determine the distribution of nitric oxide-synthesizing neurons in the oviduct of the pigeon by histochemistry for nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d). The NADPH-d reaction was seen in the neurons and fibers. NADPH-d neurons were mainly distributed around the arterioles of the intermuscular tissue in the upper oviduct (infundibulum, magnum, and isthmus); in addition, NADPH-d neurons were also seen in the smooth muscle layers and lamina propria in the lower oviduct (uterus and vagina). NADPH-d neurons were found singly or in small groups of two-eight cell bodies. The number of NADPH-d neurons was smallest in the infundibulum, gradually increased toward the vagina. NADPH-d was also shown to be strongly positive in many neurons in the ganglia of the vaginal adventitia. Bundles of NADPH-d fibers ran in the smooth muscle layer, surrounded blood vessels, or connected with small groups of NADPH-d neurons by forming strands. Thin fibers branched from these bundles and constituted a finer network in the smooth muscle layer and lamina propria. Acetylcholinesterase staining in neurons and fibers showed a similar pattern of NADPH-d distribution in the oviduct. By double staining, 70 approximately 77% of neurons showed colocalization of NADPH-d and acetylcholinesterase in the uterus and vagina. Tyrosine hydroxylase immunoreactivity stained only nerve fibers and were distributed largely around blood vessels in the oviduct. Nerve fibers immunoreactive for calcitonin-gene related peptide, galanin, methionine-enkephalin, substance P, or vasoactive intestinal peptide were found sparsely in the oviduct. These results demonstrate that nitrergic neurons make up a large subpopulation of intrinsic neurons that are closely associated with a cholinergic system in the pigeon oviduct, thus suggesting that nitric oxide and acetylcholine could be used to modify the relaxation of the avian oviduct.
Atoji
Y
Y
Laboratory of Veterinary Anatomy, Faculty of Agriculture, Gifu University, Japan. atozi@cc.gifu-u.ac.jp
Mizutani
K
K
Yamamoto
Y
Y
Suzuki
Y
Y
D000110:Acetylcholinesterase / Q000032:analysis*; D000818:Animals; D002799:Cholinergic Fibers / Q000737:chemistry*; D010856:Columbidae; D005260:Female; D009130:Muscle, Smooth / Q000737:chemistry; D009252:NADPH Dehydrogenase / Q000032:analysis*; D009415:Nerve Net / Q000737:chemistry*; D009474:Neurons / Q000737:chemistry; D009479:Neuropeptides / Q000032:analysis*; D010057:Oviducts / Q000737:chemistry* / Q000294:innervation; D014446:Tyrosine 3-Monooxygenase / Q000032:analysis*
D009479:Neuropeptides; D014446:Tyrosine 3-Monooxygenase; D009252:NADPH Dehydrogenase; D000110:Acetylcholinesterase