Mechanisms of pain relief induced by vibration and movement were investigated. A CO2 laser beam, which is useful for pure nociceptive stimulation, was used for recording pain-related somatosensory evoked potentials (pain SEPs) and for measuring pain threshold and reaction time (RT). Concurrently applied vibratory stimuli to and active movements of the fingers significantly reduced and prolonged...

This is the first examination of sensory receptive properties and associated electrophysiological properties in vivo of dorsal root ganglion (DRG) neurons that express the TTX-resistant sodium channel Na(v)1.9 (NaN). Intracellular recordings in lumbar DRGs in Wistar rats enabled units with dorsal root C-, Adelta-, or Aalpha/beta-fibers to be classified as nociceptive, low-threshold mechanorecep...

Introduction: It is known that acute and chronic stress induce hormonal and neuronal changes which affecting both pain threshold and nociceptive behaviours. Orexin plays an important role in modulation of pain and stress. Considering pain modulation during stress and the role of orexin in pain and stress, orexin might be involved in pain modulation during stress.We evaluated the involvement ...

Introduction: As sex differences have been observed repeatedly in chronic pain, it is likely that the gonadal hormones are responsible for these differences. To investigate the responsible mechanism for chronic pain different models have been created. This study is examining the effects of gonadal hormones on nociceptive responses of the rats in CCI (chronic constriction injury) and SNI (spread...

The organization and response properties of nociceptive neurons in area 1 of the primary somatosensory cortex (SI) of anesthetized monkeys were examined. The receptive fields of nociceptive neurons were classified as either wide-dynamic-range (WDR) neurons that were preferentially responsive to noxious mechanical stimulation, or nociceptive specific (NS) that were responsive to only noxious sti...

It has been proposed that extracellular ATP may be involved in visceral mechanosensory transduction by activating ligand-gated ion channels (P2X receptors). In this study, we have investigated the effects of the P2X(3) agonist alpha,beta-methylene ATP (alpha,beta-meATP) and antagonist 2',3'-O-trinitrophenyl-ATP (TNP-ATP) on pelvic afferents innervating the urinary bladder using an in vitro mous...

Considering the importance of a deeper understanding of the effect throughout life of opioid analgesia at birth, our objective was to determine whether morphine administration in early life, once a day for 7 days in 8-day-old rats, alters the nociceptive response over the short (P16), medium (P30), and long term (P60) and to evaluate which system is involved in the altered nociceptive response....

Intracellular recordings were made from 1022 somatic lumbar dorsal root ganglion (DRG) neurones in anaesthetized adult rats, classified from dorsal root conduction velocities (CVs) as C, Adelta or Aalpha/beta, and according to their responses to mechanical and thermal stimuli as nociceptive (including high-threshold mechanoreceptive (HTM) units), and non-nociceptive (including low-threshold mec...

Central sensitization is a crucial mechanism underlying the increased excitability of nociceptive pathways following peripheral tissue injury and inflammation. We have previously demonstrated that the small-fiber excitant and inflammatory irritant mustard oil (MO) applied to the tooth pulp produces glutamatergic- and purinergic-dependent central sensitization in brainstem nociceptive neurons of...

BACKGROUND Although it has been widely accepted that the primary somatosensory (SI) cortex plays an important role in pain perception, it still remains unclear how the nociceptive mechanisms of synaptic transmission occur at the single neuron level. The aim of the present study was to examine whether noxious stimulation applied to the orofacial area evokes the synaptic response of SI neurons in...