Neuropeptide Y, substance P, tyrosine hydroxylase and vasoactive intestinal polypeptide-containing nerve fibers in the rat seminal vesicle

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blunted response of sympathetic nerve activity and heart rate in hypertensive subjects underlies the maintenance of high blood pressure. (The Autonomic Nervous System, 26: 544-549, 1989)

Neuropeptide Y, substance P, tyrosine hydroxylase and vasoactive intestinal polypeptide-containing nerve fibers in the rat seminal vesicle K a z u n a r i Y u r i , M a k o t o H i r i k a w a , H i s a o Y a m a d a , T a d a o M a t s u u r a *, Y u j i A z u m a * *, T o y o h i r o T e r e s a k i * *, T o m o h i t o K i t a m o r i , N a o k i I m a d a * * a n d H i r o k i W a t a n a b e * * First Department of Anatomy, Kyoto Prefectural University of Medicine, * Department of Anatomy, Meiji College of Oriental Medicine, and * * Department of Urology, Kyoto Prefectural University of Medicine, Kyoto, Japan

We investigated by immunohistochemistry in the light and electron microscope the innervation of the rat seminal vesicle, using sections and whole-mount preparations. Primary antisera against neuropeptide Y, substance P, tyrosine hydroxylase and vasoactive intestinal polypeptide were used. Fibers immunoreactive for neuropeptide Y and tyrosine hydroxylase were found in the muscle coat, and their terminals lay in close apposition to muscle cells. A small number of fibers containing substance P were also present in the muscle coat. Vasoactive intestinal polypeptide containing fibers were present not only in the muscle coat but also in the mucosa. It is possible that fibers containing vasoactive intestinal polypeptide have a different role than fibers containing neuropeptide Y, substance P or tyrosine hydroxylase. (The Autonomic Nervous System, 26: 550-555, 1989)

Methionin-enkephalin immunoreactivity and its colocalization with catecholamine in neurons of the cardiovascular center of the brainstem of normotensiva and spontaneously hypertensive rats Sadatsugu Murakami, Yukio Ichitani, Hitoshi Okamura and Yasuhibo Ibata Department of Anatomy, Kyoto Prefectural University of Medicine, Kyoto, Japan

We investigated the distribution of methionine-enkephalin-Arg6-GlyV-LeuS(met-enk-8)-like immunoreactivity and its colocalization with catecholamine in neurons of the nucleus reticularis lateralis, the nucleus tractus solitarii, and the locus coeruleus, in 8-week-old Wistar rats. We found many met-enk-8-1ike immunoreactive neurons in the nucleus reticularis lateralis and the nucleus tractus solitarii, but almost none in the locus coeruleus. The ratio of met-enk-8-containing and catecholamine-fluorescent neurons to the total number of catecholamine fluorescent neurons was higher in the nucleus reticularis lateralis than in the nucleus tractus solitarii. A new category of catecholaminergic neurons characterized by the colocalization of enkephalin is proposed. We also investigated the distribution of this peptide in the locus coeruleus of 4-, 8- and 16-week old spontaneously hypertensive rats, and in Wistar-Kyoto rats of the same age. In the hypertensive rats, met-enk-8-1ike immunoreactive neurons were found only at 4 weeks of age. This observation suggests that in the pre-hypertensive condition of 4-week-old spontaneously hypertensive rats, met-enk-8 may play an important role in catecholamine metabolism in the locus coeruleus. (The Autonomic Nervous System, 26: 556-562, 1989)