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Dipeptidylpeptidase IV activity in Meissner corpuscles of rhesus monkey and its possible function
1Department of Anatomy, Medical Faculty, Parkynĕ University, Brno, C.S.S.R.
Abstract:
Histochemical investigation by means of light and electron microscopy revealed the presence of dipeptidylpeptidase IV activity in Meissner corpuscles of macaque glabrous skin. The enzyme activity was found in fibroblast-like cells forming an incomplete capsule around the Meissner corpuscle. Distinct electron-dense reaction product due to dipeptidylpeptidase IV activity was consistently localized in the plasma membrane of specialized Schwann cells enveloping the unmyelinated portion of sensory axons. Their axolemma was devoid of dipeptidylpeptidase IV reaction product. The membrane-bound dipeptidylpeptidase IV activity presented here and the occurrence of substance P-containing nerve fibers in primate Meissner corpuscles referred to elsewhere, suggest the possible functional involvement of the enzyme in the production of substance P fragments, influenced in different ways by the axon proper and its surrounding Schwann cells.
Insights
Dipeptidylpeptidase IV activity was found in Meissner corpuscles of macaque skin, specifically in Schwann cells surrounding sensory axons. This suggests a role in processing substance P, a key neurotransmitter.
Area of Science:
- Neuroscience
- Histochemistry
- Cell Biology
Background:
- Meissner corpuscles are mechanoreceptors crucial for tactile sensation in glabrous skin.
- The role of specific enzymes within these complex structures remains incompletely understood.
- Dipeptidylpeptidase IV (DPP IV) is an enzyme known for its involvement in peptide metabolism.
Purpose of the Study:
- To investigate the presence and localization of dipeptidylpeptidase IV activity in primate Meissner corpuscles.
- To explore the potential functional significance of DPP IV in the context of sensory axon-nerve fiber interactions.
Main Methods:
- Histochemical analysis using light and electron microscopy.
- Detection of dipeptidylpeptidase IV enzyme activity via reaction product localization.
Main Results:
- DPP IV activity was identified in fibroblast-like capsular cells and, notably, in the plasma membrane of Schwann cells ensheathing unmyelinated sensory axons within Meissner corpuscles.
- The axolemma of these sensory axons showed no DPP IV activity.
- Enzyme activity was localized to the membrane of specialized Schwann cells.
Conclusions:
- The findings indicate a specific localization of DPP IV within the Schwann cell membrane in primate Meissner corpuscles.
- This localization, coupled with the presence of substance P nerve fibers, suggests DPP IV may participate in modulating substance P activity.
- The enzyme's function could be influenced by interactions between the axon and its surrounding Schwann cells.