Morphological characteristics and distribution of the autonomic and sensitive innervation of the prostate in some animal species.

The sensitive and autonomic innervation of the prostate was studied in some mammals (rat, rabbit, horse, donkey and bull) using gold chloride impregnation. In all the species considered the gland was supplied with conspicuous innervation located in the thickness of the capsule and in trabeculae. The autonomic innervation was constituted by ganglion cells of different sizes (small, medium and large), isolated or in groups of large ganglia also, always located along the course of nerve bundles. The sensitive nervous component, placed more frequently in the most superficial layer of the capsule, consisted of delicate networks originating by more fibres and, above all, of capsulated receptors such as Pacini and Golgi-Mazzoni corpuscles. A characteristic finding, but only present in the horse, donkey and bull, was the helicoidal disposition of thin collagen fibres around thin nervous bundles that ended up to the point where the nerve trunk divided.

The nerve endings of the acetabular labrum.

The nerve endings of the human acetabular labrum were investigated. Twenty-three acetabular labra were obtained from 24 fresh human cadavers, stained with Suzuki's silver impregnation and an immunohistochemical technique for neurogenic specific protein S-100, and examined by light and electron microscopy. Ramified free nerve endings were seen in all specimens by silver staining, and also were observed by the immunohistochemical technique for S-100 protein. Sensory nerve end organs, such as a Vater-Pacini corpuscle, Golgi-Mazzoni corpuscle, Ruffini corpuscle, and articular corpuscle (Krause corpuscle), were observed by silver staining. Collagen fibers were scattered sparsely in the superficial layer of the labrum, and nerve endings were observed mostly in this region. Collagen fibers were sparse, and nerve endings also were observed in some regions among the collagen fiber bundles in the inner layer. Innervation of the acetabular labrum was confirmed in this study, suggesting that nerve endings in the labrum may be involved in nociceptive and proprioceptive mechanisms.

The occurrence and ultrastructure of a mechanoreceptor in the human cricopharyngeus muscle.

An encapsulated nerve structure resembling the Golgi tendon organ was found in a human cricopharyngeus muscle near the cricoid cartilage where muscle fibers terminate. The capsule consisted of lamellated flattened cells with a basal lamina. Capsular cells separated the lumen into small compartments which contained myelinated and/or nonmyelinated nerve fibers. Nonmyelinated nerve fibers were also found in the interlamellar spaces of the capsular cells. Some nonmyelinated nerve fibers were dilated and contained abundant mitochondria, being partly surrounded by a Schwann cell sheath and embedded in collagen bundles. These features indicate that the nerve structure is a mechanoreceptor similar to the Golgi tendon organ. Its location and structure indicate that it is placed to detect the tension of the cricopharyngeus muscle.

The fine structure of the cervical spinal cord, ventral root and brachial nerves in the wobbler (wr) mouse.

Much indirect evidence supports the prevailing concept that the wobbler mouse represents an inherited form of lower motor neuron degeneration, with resultant neurogenic muscular atrophy, due to an autosomal recessive gene (wr). This report, which emphasizes the fine structural changes in the wobbler mouse cervical spinal cord, ventral root and brachial nerves, both extends and modifies previously published data concerning the ultrastructural changes in this disorder. In addition to the more obvious neuronal cytoplasmic vacuolization known to occur, studies extended to a broader age range of wobbler mice have revealed neuronal alterations such as nonvacuolar dissolution of granular endoplasmic reticulum, proliferation of cytoplasmic microtubules and neurofilaments, proliferation of branched tubules resembling smooth endoplasmic reticulum, development of lipid droplets, and increased numbers of pleomorphic dense and lamellar cytoplasmic bodies. The spectrum of pathological changes in this murine form of motor neuron disease thus appears more complex and varied than has hitherto been appreciated, and may be relevant to the formulation of pathogenetic hypotheses.