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N Minorsky

Publications and source records attributed to N Minorsky.

7 recordsLinked to original sources
PubMed1988

Autoradiographic evidence of muscarinic cholinergic receptors in the corpora cavernosa penis of the rat.

Recent studies have questioned the role of acetylcholine in the physiology of penile erectile tissue. The responsiveness of penile erectile tissue to acetylcholine would depend, in part, on the presence of cholinergic receptors on the smooth muscle. The specific binding of [3H]quinuclidinyl benzilate (QNB) to cholinergic receptors in sections of penile crura of the rat was analyzed by in vitro neurotransmitter autoradiography. Silver grain density measurements indicated that muscarinic cholinergic receptor binding sites are located almost entirely over the corpora cavernosa penis. Virtually no specific [3H]QNB binding was present in the tunica albuginea or adjacent skeletal muscle tissue. Within the erectile tissue, specific binding occurred both over the columns of intrinsic smooth muscle which form the walls of the cavernous spaces and around the more distal branches of the penile arteries. The high concentration of muscarinic cholinergic receptors in the corpora cavernosa penis is consistent with the suggestion that acetylcholine has an important, albeit undefined role in the function of penile erectile tissue.

Animals↗
PubMed1987

Responses of smooth muscle strips from penile erectile tissue to drugs and transmural nerve stimulation.

1. The mechanical response to drugs and to electrical stimulation of nerves was investigated in isolated strips of intrinsic smooth muscle from the corpora cavernosa penis of the rat. 2. Noradrenaline caused muscle strips to contract in a dose-dependent manner. Contractions could be blocked by pretreatment with the alpha-adrenoreceptor antagonist, phentolamine. 3. Acetylcholine and carbachol had no effect on the baseline tension of muscle strips. Both drugs were relatively ineffective in relaxing noradrenaline-contracted strips. 4. Field stimulation of isolated muscle strips elicited contractions which were blocked by tetrodotoxin and greatly attenuated with phentolamine or reserpine pretreatment. Acetylcholine inhibited the excitatory response to field stimulation. This inhibitory effect of acetylcholine could be blocked with atropine. 5. Field stimulation of noradrenaline-contracted muscle strips caused relaxation. This inhibitory effect, due to nerves which arise from the pelvic plexus, is unaffected by substances which act on cholinergic systems. 6. The results suggest that the erectile muscle of the rat is similar to that of man in that it receives an excitatory noradrenergic innervation and an inhibitory innervation which may have a non-cholinergic component. Although acetylcholine may have a role in penile physiology of the rat, it is unlikely that it has a postsynaptic action.

Acetylcholine↗
PubMed1986

Composition of the pelvic nerve.

Surgical interruption of the pelvic nerve elevated immunoreactive vasoactive intestinal polypeptide in the major pelvic ganglion of the rat. Two changes were noted: (i) varicose and smooth fibers appeared in the neuropil and (ii) a small number of ganglion cells became highly reactive for the polypeptide. A more proximal transection of preganglionic parasympathetic fibers, at their origin from spinal nerves, had no effect on vasoactive intestinal polypeptide immunoreactivity. Ganglion cells were labeled when a dye was applied to the cut distal end of the pelvic nerve. We conclude that a population of vasoactive intestinal polypeptide-containing neurons in the major pelvic ganglion send their axons proximally in the pelvic nerve.

Animals↗
PubMed1986

The hypogastric nerve pathway to penile erectile tissue: histochemical evidence supporting a vasodilator role.

Retrograde dye staining, combined with histochemical and immunohistochemical techniques, were used to characterize penile neurons in the major pelvic ganglion of the rat. Of the penile neurons 92% were immunoreactive for vasoactive intestinal polypeptide, while 95% of penile neurons stained intensely for acetylcholinesterase. None of the neurons were immunoreactive for tyrosine hydroxylase. Penile neurons in the pelvic plexus receive preganglionic input from the pelvic and the hypogastric nerve, yet the shared histochemical features of the postganglionic neurons suggest that the two pathways have a similar role in penile erectile tissue.

Acetylcholinesterase↗
PubMed1985

The hypogastric nerve innervates a population of penile neurons in the pelvic plexus.

Retrograde dye staining, enkephalin immunocytochemistry and nerve lesion paradigms were used to determine if penile neurons in the pelvic plexus are innervated by fibers in the hypogastric nerve. In the intact major pelvic ganglion of the rat, some 80% of penile neurons are enclosed by an enkephalin-positive fiber plexus. Following surgical interruption of the pelvic nerve, 20% of penile neurons were still surrounded by an enkephalin plexus. After interruption of the pelvic nerve and the hypogastric nerve, the enkephalin plexus in the ganglion was virtually absent, including the plexus around penile neurons. Therefore, possible intrinsic sources of the enkephalin fibers such as enkephalin-positive principal neurons and small intensely fluorescent cells, do not account for the delicate enkephalin fiber system in the pelvic ganglion. It is concluded that the pelvic nerve is the major source of preganglionic innervation to penile neurons in the major pelvic ganglion. However, it is significant that the hypogastric nerve is preganglionic to about 20% of penile neurons. The pathway through the hypogastric nerve may represent an alternate vasodilator system to penile erectile tissue.

Animals↗