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Acta Physiologica 2011; Volume 202, Supplement 684
The Joint Conference (FAMÉ 2011) of the LXXVth Meeting of the Hungarian Physiological Society, XVIth Meeting of the Hungarian Society of Anatomists, Experimental Section of the Hungarian Society for Experimental and Clinical Pharmacology and Hungarian Society for Microcirculation and Vascular Biology
6/8/2011-6/11/2011
Pécs, Hungary
EXPRESSION OF INSULIN RECEPTORS IN IDENTIFIED VISCERAL PRIMARY AFFERENT NEURONS AND THEIR CO-LOCALIZATION WITH THE CAPSAICIN RECEPTOR TRPV1
Abstract number: O50
Santha1 P., Nagy2 I., Jancso1 G.
Aims:
Possible target specific differences in the distribution of insulin receptors (InsRs) and their colocalizations with TRP vanilloid type 1 (TRPV1) and melastatin type 8 (TRPM8) receptors and calcitonin gene-related peptide (CGRP) were examined in rat primary sensory neurons.
Methods:
Retrograde labeling experiments with diamidino-yellow revealed a significantly higher proportion of labeled InsR+ dorsal root ganglion (DRG) neurons innervating the urinary bladder (47±6%) as compared with the skin (16±4%) or skeletal muscle (19±3%). Therefore, the colocalization of InsR with thermo-sensitive TRP channels and CGRP was studied in retrogradely labeled visceral DRG neurons serving the urinary bladder and pancreas. Wheat germ agglutinin conjugated with biotin (bWGA) or choleratoxin B subunit conjugated with fluorescein isothiocyanate (CTB-FITC) was injected into the wall of the urinary bladder or into the pancreas to label visceral DRG neurons. Three days later, the animals were sacrificed and the Th9-S1 DRGs and the nodose ganglia were processed for immunohistochemistry.
Results:
In the DRGs, numerous neurons were retrogradely labeled with both bWGA and CTB-FITC; the proportion of labeled TRPV1+ neurons was greater after injection of bWGA. Colocalization of the TRPV1 and the InsR was seen in 27±5% and 15±3% of neurons labeled retrogradely from the urinary bladder with bWGA and CTB-FITC, respectively. In DRG neurons retrogradely labeled with bWGA from the pancreas, the proportion of neurons exhibiting TRPV1/InsR double labeling amounted to 25±4%. The proportion of DRG neurons showing colocalisation of InsR-CGRP amounted up to 23% (bladder) and 16% (pancreas). In the nodose ganglia only few TRPV+/InsR+ neurons were found.
Conclusion:
The present study disclosed a more abundant expression of InsRs in TRPV1+ visceral DRG neurons as compared to somatic ones and suggests that potentiation of the TRPV1 receptor function by InsR activation, as observed in vitro, may play a distinct role in visceral nociceptive and inflammatory mechanisms.
Support:
OTKA PD73259, K 63663 and TÁMOP 4.2.1/B-09/1/KONV-2010-0005
To cite this abstract, please use the following information:
Acta Physiologica 2011; Volume 202, Supplement 684 :O50