Enzyme histochemistry of cutaneous sensory nerve formations.

The cutaneous sensory nerve formations belong to the structures which are studied intensely by the enzyme activity histochemistry since the early history of this technique. The histochemical localization of the activities of nonspecific cholinesterase, alkaline phosphatases, acid phosphatase, adenosine tri- and diphosphatases, adenylate cyclase, and dipeptidylpeptidase-IV in the cutaneous sensory nerve formations, mainly sensory corpuscles, is reviewed. The histochemical approach has brought new knowledge of both morphological building of these unique structures and their biochemical constituents. Taken together, the present results of enzyme histochemistry provide insight into the function of enzymes, and disclose new relationships between the sensory terminals and auxiliary structures in the cutaneous sensory nerve formations.

Protein kinase C (alpha, beta, gamma) in Pacinian corpuscle.

Immunocytochemical demonstration of protein kinase C (PKC) subspecies (alpha, beta, gamma) was carried out in Pacinian corpuscles of rat hind feet using monoclonal or polyclonal antibodies against each of these subspecies. The inner core cells and lamellae and the Schwann cell cytoplasm of the nerve fiber innervating the corpuscle were strongly positive for PKC alpha-immunoreactivity (IR). In contrast, the axon terminal and the outer core did not display any positive alpha-IR. Very weak PKC beta-IR was detected in the ultraterminal region of the axon terminal, while the trunk region showed no immunoreactivity. Very faint PKC beta-IR was found also in the lamellar cells located at the periphery of the inner core and the endoneurial fibroblasts in the intermediate layer. PKC gamma-IR was not detected in any part of the corpuscle. The strong PKC alpha-IR in the inner core and the presence or absence of PKC alpha-, beta-, and gamma-IR in the axon terminal are discussed from the point of view of the functional aspects of each part.

Fluoride resistant acid phosphatase activity in pacinian corpuscles of the cat mesentery. Light microscope.

Fluoride-resistant acid phosphatase (extralysosomal) activity has been investigated in Pacinian sensory corpuscles from cat's mesentery. The activity was found in the innermost and intermediate layers of the capsular system, but it is not possible to establish its exact localization. The central axon and the inner core were FRAP negative. The authors discuss the possible functional significance of FRAP activity in sensory corpuscles.

Electron microscopical localization of non-specific cholinesterase activity in three principal parts of cat Pacinian corpuscles.

Non-specific cholinesterase (nCHE) activity was demonstrated histochemically on electron microscope level in 3 parts of Pacinian corpuscles from the cat mesenterium. The reaction product was abundant on the plasmic membrane of the inner core lamellae. Schwann cells of a myelinated portion of a sensory axon in Pacinian corpuscles were devoid of positive reaction to nCHE activity. These results are in agreement with those obtained in other sensory nerve endings. Therefore, the cells investing the terminal portion of an unmyelinated sensory axon are considered to be specialized Schwann cells. Furthermore, the amount of end product was lower on the specialized Schwann cells around ultraterminal than terminal portion of a sensory axon. A significantly higher nCHE activity confined to the inner core around the terminal portion of a sensory axon suggests the participation of this enzyme in the maintenance of ionic milieu in periaxonal microenvironment.

The electron microscopic localization of alkaline phosphatase in Pacinian corpuscles of the cat.

The ultrastructural localization of alkaline phosphatase has been studied in Pacinian corpuscles of the cat mesentery by the method of Mayahara et al. (1967) with 3 substrates. As control studies, specimens were incubated in the medium containing L-cysteine (10 mmol) or EDTA (5 mmol). The electron opaque final reaction product was observed on plasmic membranes and in cytoplasm and pinocytotic vesicles of the inner core cells. The precipitate was present also in rough endoplasmic reticulum, multivesicular bodies, and cytoplasmic vacuoles of the inner core lamellae. The axon revealed the positive enzymatic activity in the axolemma and the scattered precipitate was found in axoplasm. The pinocytotic vesicles in the capillary endothelium entering Pacinian corpuscles contained the reaction product, too. The capsule lamellae were devoid of precipitate. Localization of alkaline phosphatase in pinocytotic vesicles of the inner core lamellae and capillary wall support the opinion that this enzyme plays the significant role in the phenomenon of the transport of molecules through inner core lamellae from capillaries to the axon in Pacinian corpuscles.

[Cholinesterase activity in the Pacinian corpuscles in denervation and the application of colchicine to the nerve]. / Aktivnost' kholinesteraz tel'tsakh Pachini pri ikh denervatsii i applikatsii kolkhitsina na nerv.

In the Pacinian corpuscles, cholinesterase activity was predominantly revealed along the plasma membrane and in the cytoplasm of the inner core cells. A faint quantity of histochemical end product was detected in the axis cylinder. An increased cholinesterase activity was found after the nerve transection. This change coincides in time with phagocytosis of degenerated axis cylinder by the inner core cells. A decrease in cholinesterase activity was observed in the Pacinian corpuscles after colchicine application to the nerve. This effect may be due to either the blockade of axoplasmic transport of cholinesterase in afferent nerve or/and to the elimination of the trophic influence exerted by the nerve on the cholinesterase activity in the inner care cells.

[Characteristics of lactate dehydrogenase isoenzyme distribution in Pacinian corpuscles]. / Osobennosti raspredeleniia izofermentov laktatdegidrogenazy v tel'tsakh Pachini.

The paper deals with the isoenzymic LDG composition in different sections of Pacinian corpuscles. It is found that intracapsular liquid has the aerobic LDG spectrum. The stromal part of the receptor including lamellar capsule structures, inner cone and nerve endings has the anaerobic LDG spectrum. A conclusion is drawn that LDG aerobic LDG spectrum in the intracapsular liquid of Pacinian corpuscles confirms that the liquid is well saturated with oxygen.

Electron-microscopic localization of cholinesterase activity in Pacinian corpuscles of the cat mesentery.

The authors studied nCHE activity in Pacinian corpuscles of the mesentery of adult cats and 14-day-old kittens. The localization of nCHE was performed on non-frozen sections in Karnovsky's method (1964) with inhibitor application. The nCHE activity was by means of reaction product deposits always localized on plasmic membranes of inner core lamellae and on the axon axolemma. On capsule lamellae no nCHE activity was found. In inner core cells of Pacinian corpuscles of adult individuals, owing to sporadic occurrence of organelles their relationship to nCHE activity failed to be established. It was possible only in Pacinian corpuscles of 14-day-old kittens, where organelle findings are substantially more frequent and furthermore the lamellae broader, which facilitates the localization of deposits on plasmic membranes. The nCHE activity was proved here on the rough endoplasmic reticulum and on vesicles of the Golgi complex. For the above-mentioned reasons Pacinian corpuscles of kittens are substantially more suitable for the ultrahistochemical localization of enzymes than those of adult cats. The difference in nCHE activity localization, as it was established by Idé and Saito (1980), is probably caused by the different preparation of sections for incubation (cryostat sections were used). The occurrence of nCHE isoenzymes with different binding to the membranes of inner core cells of the Pacinian corpuscle not only renders exact electron-microscopic localization more difficult but it also shows that, similarly as ACHE, nCHE is synthetized in the rough endoplasmic reticulum in soluble oligomeric form. Only after aggregation of these subunits is it bound to the membranous structures of the inner core. The reversibility of this process can explain the irregular findings of the precipitate, mainly on pinocytotic vesicles. The localization of nCHE on inner core cells supports the opinion that inner core lamellae of Pacinian corpuscles are formed by Schwann cells. The nCHE activity found on all inner core lamellae of Pacinian corpuscles from the axon to the capsule lamellae is further evidence for the nonexistence of a special zone of lamellae, the so-called outer core, between the inner core and capsule.

[Study of individual Pacinian corpuscle mechanoreceptors following application of colchicine to a nerve]. / Izuchenie odinochnykh mekhanoretseptorov telets Pachini pri applikatsii kolkhitsina na nerv.

Colchicine application to the cat caudal mesenteric nerve containing sensory fibers for single mechanoreceptors (Pacinian corpuscles) causes degeneration of the axis cast of the nerve endings. Ultrastructural changes in the receptors showed no difference from the axonal degeneration after the nerve section but the rate of degeneration was considerably slower. Ultrastructural, electrophysiological, and biochemical changes occurring in the Pacinian corpuscles were not the result of direct action of colchicine, but appeared to be realized through the nerve by the axoplasmic transport block. It is suggested that the receptor's structure is under the sensory neuron neurotrophic control.

[Mg, Ca-activated ATP-ase of Pacinian corpuscles]. / Mg, Ca-aktiviruemaia ATF-aza telets Pachini

Adenosine triphosphatase (ATPase) activated by Mg2+ or Ca2+ ions was detected in single mechanoreceptors (Pacini's corpuscles) of cat; addition of Ca2+ (10(-5)M) to Mg-ATP-ase increased the activity by the factor of 1.6. The activity optimum of Mg- or Co-ATPase was in the alkaline pH zone. A high substrate specificity of Mg, Ca-ATPase was shown. Parachlorinemercury-benzoate (5muM) considerably reduced the activity of Mg, Ca-ATPase, whereas oubain (10(-5)M) failed to affect it significantly. It is supposed that Mg, Ca-ATPase of Pacini's corpuscles was close to actomyosine -like proteins.