This study investigated the effects of intracerebroventricular (ICV) and intra-arcuate nucleus (ARC) injection of ghrelin on pain behavioral responses and levels of β-endorphin (β-EP) and met-enkephalin (MENK) in the periaqueductal gray area (PAG) during the formalin test in rats.
In this study, we report that α-MSH suppresses the transient outward A-type K<sup>+</sup> current (<i>I</i><sub>A</sub>) in trigeminal ganglion (TG) neurons and thereby modulates neuronal excitability and peripheral pain sensitivity in rats.
Regression analyses indicated that β-endorphin level was negatively related to pressure pain threshold (β = -17.18, <i>p</i> = .02) and positively related to punctate mechanical pain (β = 17.13, <i>p</i> = .04), after controlling for age, gender, and OA severity.
The role of Oxycontin was analyzed by collecting the patients' general information, age, gender, Karnofsky performance status (KPS) score, site of pain and degree of pain, and by detecting the remission rates of clinical symptoms, average analgesic time, number of pain outbreak per day, levels of β-EP, CGRP and PGE2, as well as changes of KPS score, Zubrod performance status (ZPS) score and quality of life (QoL) score of the enrolled patients before treatment and at 1 week afer treatment.
Physiological parameters (heart rate, respiratory rate, rectal temperature, invasive blood pressure, cortisol, β-endorphin, interleukin-1β, interleukin-6, tumor necrosis factor-α and haptoglobin plasmatic concentration), local variables (tactile sensitivity score, pressure pain thresholds and horn temperature), behavior and pain scores [multidimensional pain scale and visual analogue scale (VAS)] were assessed at baseline and at several pre-determined time points until 24h after disbudding.
Despite some evidence that indicates that the evolution of polycystic ovary syndrome (PCOS) is related to the activity of the endogenous opioid system, and that concentration of plasma β-endorphin levels can increase pain threshold, there are no studies which evaluate pressure pain threshold in the PCOS women population.
The plasma β-endorphin levels were significantly higher in controls than in pain patients.A higher incidence of opioid-related side effects and sex differences was found in patients with the minor allele of the ABCB1 gene.
We review recent findings on molecular adaptations in sustained pain models, and propose how these adaptations (including sustained release of the endogenous mu-agonist beta-endorphin) can result in decreased abuse potential of mu-agonists in chronic pain states.
These data demonstrate the efficacy of the preproenkephalin A encoding vector and suggest that it should help in elucidating the role of Met-enkephalin-containing primary afferent fibers in pain transmission and/or control.
We previously reported that polymer-encapsulated mouse neuroblastoma cells that are capable of secreting beta-endorphin may reduce pain sensitivity in rats after capsule implantation into the cerebrospinal fluid (CSF)-filled subarachnoid space of the spinal cord.