The role of sex and gender in accounting for individual pain behaviors is poorly understood. The present study was conducted to determine whether neonatal nociceptive stimuli at postnatal day 1 (PD1) in rats would lead to a differential behavioral impact based on gender. Animals were divided in 4 groups according to treatment (two injections of 4% formalin into the pad of right paws at PD1 or c...

1. In view of the presence of mu, delta and kappa opioid receptors in the spinal dorsal horn and their apparent involvement in behavioural analgesia, the present experiments addressed the action of selective agonists ionophoresed in the vicinity of rat dorsal horn neurones which were located either in lamina I or in laminae III-V. 2. In laminae III-V, kappa agonists (U50488H and dynorphin A) ca...

Aim: The aim of this study was to verify the pain behavior to electroacupuncture (EACP) in rabbit tooth-pulp assay. Methods: Albino rabbits weighing 1.5-2.0 kg) were pretreated with saline or morphine (5mg/kg, e.v.) 10 min before the nociceptive test (NT). In another group, EACP (rectangular pulses, f1=2 Hz, f2=0.1 s, 3 mA) was applied in acupoints and sham points, before and during the NT. Aft...

The nociceptive noxious heat-activated receptor - TRPV1, conducts calcium and sodium, thus producing a depolarizing receptor potential, leading to activation of nociceptive neurons. TRPV1-mediated calcium and sodium influx is negatively modulated by calcium, via calcium-dependent desensitization of TRPV1 channels. A mitochondrial Ca2+ uniporter - MCU, controls mitochondrial Ca2+ entry while a s...

It is currently accepted that superoxide anion (O2•-) is an important mediator in pain and inflammation. The role of superoxide anion in pain and inflammation has been mainly determined indirectly by modulating its production and inactivation. Direct evidence using potassium superoxide (KO2), a superoxide anion donor, demonstrated that it induced thermal hyperalgesia, as assessed by the Hargrea...

Visceral pain is an important therapeutic problem. A number of studies have established that abdominal vagal afferents modulate somatic pain behavior. Although it is not clear if vagal afferents transmit nociceptive information, a change in their activity can increase or decrease nociceptive transmission in visceral pain. Aims of the present study were to determine whether the subdiaphragmatic ...

The processing of pain undergoes several changes in aging that affect sensory nociceptive fibers and the endogenous neuronal inhibitory systems. So far, it is not completely clear whether age-induced modifications are associated with an increase or decrease in pain perception. In this study, we assessed the impact of age on inflammatory nociception in mice and the role of the hormonal inhibitor...

Salvinorin A, is a structurally unique, non-nitrogenous, kappa opioid receptor (KOP) agonist. Given the role of KOPs in analgesic processes, we set out to determine whether salvinorin A has antinociceptive activity in thermal and chemo-nociceptive assays. The tail-flick assay was employed to investigate 1) salvinorin A's (0.5, 1.0, 2.0, and 4.0 mg/kg) dose-response and time-course (10, 20, and ...

Chronic pain is classified as nociceptive or neuropathic, depending on whether the integrity of the somatosensory nervous system is compromised by the underlying disease. Nociceptive pain results from the activation of receptors (nociceptors) sensitive to noxious stimuli. Prolonged or intense exposure to these stimuli, for example, chemical mediators released during inflammation, enhances the r...

Intracellular pH is a fundamental parameter to cell function that requires tight homeostasis. In the absence of any regulation, excessive acidification of the cytosol would have the tendency to produce cellular damage. Mammalian Na(+)/H(+) exchangers (NHEs) are electroneutral Na(+)-dependent proteins that exchange extracellular Na(+) for intracellular H(+). To date, there are 9 identified NHE i...