The Insulin Receptor Is Colocalized With the TRPV1 Nociceptive Ion Channel and Neuropeptides in Pancreatic Spinal and Vagal Primary Sensory Neurons

Abstract

The present findings provide morphological basis for possible functional interactions among the nociceptive ion channel TRPV1, the InsR, and the proinflammatory neuropeptides SP and CGRP expressed by pancreatic DRG and NG neurons.

Modulation of Sensory Nerve Function by Insulin: Possible Relevance to Pain, Inflammation and Axon Growth

“…Further, neuropeptides contained in sensory nerves, such as SP and CGRP may modulate inflammatory processes of both the endocrine and exocrine pancreas. Quantitative immunohistochemical findings supported these findings by showing that the majority of pancreatic vagal and spinal DRG neurons express the TRPV1 receptor, the InsR and sensory neuropeptides [25].…”

“…It has been demonstrated that about 50% of DRG and nodose ganglia (NG) neurons innervating the rat pancreas express the InsR [25]. It has also been shown that up to 50% of InsR-expressing pancreatic spinal and vagal PSNs exhibit TRPV1 receptor immunoreactivity [25]. Further, about 30% of InsR-expressing pancreatic spinal and vagal sensory neurons contain SP.…”

“…Further, about 30% of InsR-expressing pancreatic spinal and vagal sensory neurons contain SP. CGRP is contained in about 60% and 20% of spinal and vagal PSNs, respectively [25]. Moreover, it has been revealed that up to 30% of TRPV1 receptor-expressing pancreatic spinal and vagal PSNs exhibit InsR immunoreactivity [25].…”

“…CGRP is contained in about 60% and 20% of spinal and vagal PSNs, respectively [25]. Moreover, it has been revealed that up to 30% of TRPV1 receptor-expressing pancreatic spinal and vagal PSNs exhibit InsR immunoreactivity [25]. In addition, up to one-quarter of CGRP or SP containing pancreatic spinal and vagal sensory neurons express the InsR as well [25].…”

“…In recent years, electrophysiological, immunohistochemical and functional studies demonstrated the localization and functional significance of InsRs in primary sensory neurons (PSNs), in particular nociceptive PSNs expressing the transient receptor potential vanilloid type 1 (TRPV1) receptor [19][20][21][22][23][24][25]. The present review attempts to summarize experimental data on the diverse roles of insulin and InsRs in physiological and pathophysiological processes involving PSNs.…”