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Immunohistochemical evidence suggests intrinsic regulatory activity of human eccrine sweat glands
C Zancanaro1, F Merigo, C Crescimanno
1Institute of Human Anatomy and Histology, University of Verona, Italy. Carloz@borgoroma.univr.it
Insights
Human sweat glands contain regulatory peptides and enzymes for nitric oxide and acetylcholine synthesis. This suggests intrinsic regulation of sweat glands, beyond nerve supply control.
Area of Science:
- Human physiology
- Sweat gland biology
- Neuroendocrinology
Background:
- Eccrine sweat glands play a role in thermoregulation.
- The intrinsic regulatory mechanisms of human sweat glands are not fully understood.
- Nerve supply to sweat glands is known, but local control is less clear.
Purpose of the Study:
- To investigate the presence and localization of specific regulatory peptides and enzymes within human eccrine sweat glands.
- To determine if sweat glands possess intrinsic regulatory capabilities.
Main Methods:
- Immunohistochemistry on human skin paraffin sections.
- Utilized antibodies against neuron-specific enolase, S100 protein, CGRP, SP, NOS-I, ChAT, and cytokeratin.
- Electron microscopy was employed to examine cellular structures.
Main Results:
- Neuron-specific enolase, S100, CGRP, SP, NOS-I, and ChAT were detected in nerve bundles and/or secretory cells.
- Granulated cells showed CGRP positivity, while parietal cells were positive for S100 and SP.
- Myoepithelial cells exclusively expressed NOS-I and ChAT.
- Electron microscopy confirmed peptide-containing granules in granulated cells.
Conclusions:
- Human sweat glands contain regulatory peptides (CGRP, SP) and enzymes (NOS-I, ChAT) involved in vasodilation and neurotransmitter synthesis.
- These findings support the hypothesis of intrinsic regulatory mechanisms within the secretory coil of human sweat glands.
- Human sweat glands may possess a degree of self-regulation independent of extrinsic nerve supply.
Abstract:
Immunohistochemistry of normal eccrine sweat glands was performed on paraffin sections of human skin. Immunoreactivity (ir) for neuron specific enolase, S100 protein (S100), regulatory peptides, nitric oxide synthase type I (NOS-I) and choline-acetyltransferase (ChAT) was found in small nerve bundles close to sweat glands. In the glands, secretory cells were labelled with anticytokeratin antibody. Using antibodies to S100, calcitonin gene-related peptide (CGRP) and substance P (SP) a specific distribution pattern was found in secretory cells. Granulated (dark) and parietal (clear) cells were immunopositive for CGRP, and S100 and SP, respectively. Immunoreactivity was diffuse in the cytoplasm for CGRP and S100, and peripheral for SP. Myoepithelial cells were not labelled. Electron microscopy revealed electron dense granules, probably containing peptide, in granulated cells. Using antibodies to NOS-I and ChAT, ir was exclusively found in myoepithelial cells. Immunoreactivity for the atrial natriuretic peptide was absent in sweat glands. These results provide evidence for the presence of both regulatory peptides involved in vasodilation and key enzymes for the synthesis of nitric oxide and acetylcholine in the secretory coil of human sweat glands. It is suggested that human sweat glands are capable of some intrinsic regulation in addition to that carried out by their nerve supply.