The innervation of Meissner's corpuscles (Mc) is complex, consisting of different types of sensory nerve fibers. We investigated the neurochemistry of Mc in human digital skin by indirect immunofluorescence, using a wide panel of both general neuronal as well as neurotransmitter-related molecules. Structural proteins (protein gene product 9.5, neuron-specific enolase, neurofilament) were found to consistently label the entire neuronal component of Mc. Immunoreactivity for gamma-melanocyte stimulating hormone was detected in the large diameter fibers running spirally within the corpuscles, while a number of peptide transmitters (substance P, calcitonin gene-related peptide, neurokinin A, galanin, somatostatin) were found in the thin unmyelinated fibers in both intra- and extracorpuscular locations.

Adult↗

PubMedDate not supplied

Somatostatin-like immunoreactivity is found in dendritic guard cells of human sweat ducts.

Somatostatin is reported in a new population of human sweat duct cells. The epithelial content of somatostatin-like immunoreactivity in normal human skin from various sites of the body was investigated using indirect immunofluorescence. With this methodology we found round-to-oval somatostatin-immunoreactive cells situated outside the lining sweat duct cells at the level of the stratum spinosum. The cells had processes that were clearly directed towards the duct lumen, passing between the lining duct cells. This finding raises new questions and ideas about somatostatin's role in the skin, and could point to a possible involvement of somatostatin in immune defense, sweat secretion modification, antiproliferation, or other actions.

Dendritic Cells↗

PubMedDate not supplied

Morphometric characterization of transmitter-identified nerve cell groups: analysis of mesencephalic 5-HT nerve cell bodies.

Morphometric techniques have been used to introduce criteria to objectively define transmitter-identified nerve cell groups and subpopulations of nerve cells within such groups. The present method is exemplified on two coronal sections of the midbrain, in which 5-HT immunoreactive nerve cell bodies have been visualized. The reliability of the method is shown by the fact that it makes it possible not only to recognize groups B7, B8 and B9 of Dahlström and Fuxe [5] but also to assess the existence of two subpopulations within group B7 as previously suggested by Fuxe and Jonsson [11] based on subjective evaluations. Furthermore, the suggestion could be made that a small assembly of 5-HT nerve cell bodies in the dorsal part of the mesencephalic tegmentum may form a new 5-HT cell group. Hence, the present method offers the advantage of assessing the existence of transmitter-identified nerve cell groups on the basis of objective criteria and to describe them in a quantitative fashion. Therefore, it allows quantitation of morphological changes occurring in transmitter-identified neurons under different experimental and pathological conditions.

Animals↗

PubMedDate not supplied

A morphometric analysis of transmitter identified dendrites and nerve terminals.

The present method is exemplified on coronal sections of the medulla oblongata containing phenylethanolamine-N-methyltransferase (PNMT) immunoreactive nerve cell bodies and their processes and on coronal sections of the pons containing the locus coeruleus, where PNMT immunoreactive nerve terminals have been demonstrated together with the dopamine-beta-hydroxylase immunoreactive nerve cell bodies. Morphometric analysis of the processes (both length and branches) and of the nerve terminals involve as a first step the division of the area under study into squares 100 microns wide, which are superimposed on a Cartesian plane. The uniformity of the density distribution of the nerve terminals and the processes (branches or length) can be analyzed by Lorenz curves, which in a quantitative way can measure the degree of unevenness and thus represent a measure of concentration. A concentration index can therefore be calculated. By the use of the densitometric approach it also becomes possible to study the density distribution of the nerve terminals with the highest antigen contents. The present method will make it possible to quantitate morphological changes occurring in processes and nerve terminals of transmitter-identified neurons.

Animals↗

PubMedDate not supplied

Cutaneous nerve distribution in adult rat hairy skin after thermal injury--an immunohistochemical study.

Regrowth of cutaneous nerves after thermal injury was examined in rat hairy skin with use of protein gene product 9.5, which has been shown to label nerves in skin preparations. Tissue biopsies were obtained from injured and control skin at postburn days 1, 7, 14, 28, and 120, fixed in 4% paraformaldehyde, cryoprotected, sectioned, and immunostained with rhodamine conjugated goat anti-rabbit immunoglobulin G. Immunoreactivity for protein gene product 9.5 was intense and illustrated the process of nerve regrowth in rat skin after thermal injury. No nerve growth was detectable in 1- and 7-day preparations. Variable regeneration was noted in 14-day preparations. The 28- and 120-day groups produced nerve counts that were similar to control sections. Results suggest that rat hairy skin has a capacity for nerve regrowth after thermal injury. Nerves were noted to regenerate from beneath the scar. Burn wounds in rats demonstrated vigorous cutaneous nerve regeneration.

Animals↗