Jonathan Edwards
Senior Member (Voting Rights)
It looks as if CRH very much does have other functions and ones of direct relevance to ME/CFS, fibromyalgia and dorsal root ganglia (and maybe CA10):
CRH is expressed in peripheral tissues outside of the central nervous system (CNS) and directly exerts extensive effects on cardiovascular, reproductive, digestive, and immune systems (15). Gastrointestinal CRH delays the motility of the gastrointestinal tract response to stress and even enhances visceral pain, a predominant feature of irritable bowel syndrome (IBS). Immunostaining has revealed CRH-positive neurons in the DRG and TG, as well as CRH-positive fibers in the superficial layer of the spinal cord and trigeminal complex in the medulla, where the central terminals of primary nociceptive neurons end (16). Under the neuropathic state, CRH expression is increased in damaged DRG neurons; however, whether and how CRH tunes pain signals at the DRG and spinal cord level remains unclear (17).
CRH receptors (CRHR1 and CRHR2) belong to the G protein–coupled receptor (GPCR) superfamily, members of which are widely distributed in nervous and peripheral tissues and integrate the responses of these tissues to various internal and external stimuli. Peripheral CRHR1 and CRHR2 mediate diverse functions in different organs. Pharmacologic data have shown that CRHR1 and CRHR2 play a counteracting role in the occurrence of visceral pain induced by colorectal distention (18). Multiple experimental studies have showed that CRH receptors (CRHR1 and CRHR2) are expressed in primary sensory neurons, the spinal cord, and the trigeminal complex in the medulla under normal and neuropathic pain conditions (16, 19–21). Thus, CRH might act on its receptors to tune the pain signals in the DRG and spinal cord after peripheral nerve injury.
Here, we investigated the function of DRG-localized CRH in persistent and chronic neuropathic pain. Through analysis of public datasets and a mouse model, we found that CRH expression in small- and medium-sized neurons of the DRG is induced in a transcription-dependent manner after peripheral nerve injury and mediates a persistent neuropathic pain state through activation of its receptor CRHR2 on dorsal spinal neurons. The findings reveal potential targets for alleviating neuropathic pain caused by peripheral nerve injury.
CRH is expressed in peripheral tissues outside of the central nervous system (CNS) and directly exerts extensive effects on cardiovascular, reproductive, digestive, and immune systems (15). Gastrointestinal CRH delays the motility of the gastrointestinal tract response to stress and even enhances visceral pain, a predominant feature of irritable bowel syndrome (IBS). Immunostaining has revealed CRH-positive neurons in the DRG and TG, as well as CRH-positive fibers in the superficial layer of the spinal cord and trigeminal complex in the medulla, where the central terminals of primary nociceptive neurons end (16). Under the neuropathic state, CRH expression is increased in damaged DRG neurons; however, whether and how CRH tunes pain signals at the DRG and spinal cord level remains unclear (17).
CRH receptors (CRHR1 and CRHR2) belong to the G protein–coupled receptor (GPCR) superfamily, members of which are widely distributed in nervous and peripheral tissues and integrate the responses of these tissues to various internal and external stimuli. Peripheral CRHR1 and CRHR2 mediate diverse functions in different organs. Pharmacologic data have shown that CRHR1 and CRHR2 play a counteracting role in the occurrence of visceral pain induced by colorectal distention (18). Multiple experimental studies have showed that CRH receptors (CRHR1 and CRHR2) are expressed in primary sensory neurons, the spinal cord, and the trigeminal complex in the medulla under normal and neuropathic pain conditions (16, 19–21). Thus, CRH might act on its receptors to tune the pain signals in the DRG and spinal cord after peripheral nerve injury.
Here, we investigated the function of DRG-localized CRH in persistent and chronic neuropathic pain. Through analysis of public datasets and a mouse model, we found that CRH expression in small- and medium-sized neurons of the DRG is induced in a transcription-dependent manner after peripheral nerve injury and mediates a persistent neuropathic pain state through activation of its receptor CRHR2 on dorsal spinal neurons. The findings reveal potential targets for alleviating neuropathic pain caused by peripheral nerve injury.