The involvement of supraspinal alpha-adrenergic receptors in tonic pain was assessed in formalin-induced pain in rats. The alpha2 adrenoceptor agonist clonidine, along with yohimbine and prazosin, α2 and α1 receptor antagonists, were introduced intracerebroventrically (icv) and/or systemically in different doses. The data show that 1) clonidine exerts an alpha adrenergic analgesic effect, ...

The role of mu-opioid receptors (MORs) in the inflammatory pain processing mechanisms within the ventrobasal complex of the thalamus (VB) is not well understood. This study investigated the effect of modulating MOR activity upon nociception, by stereotaxically injecting specific ligands in the VB. Nociceptive behaviour was evaluated in two established animal models of inflammatory pain, by usin...

The effect of a conditioning bradykinin application on histamine induced excitation of cutaneous nociceptors and on histamine induced sensations of volunteers was studied. Using an in vitro skin nerve preparation, unmyelinated polymodal nociceptor units of rats (n = 11) were tested by bathing their receptive fields from the corium side with 10(-5) M solutions of bradykinin and histamine. Follow...

introduction: 17&beta-estradiol; modulates nociception by binding to the estrogenic receptors and also by allosteric interaction with other membrane-bound receptors like glutamate and gabaa receptors. in addition to its autonomic functions, paragigantocellularis lateralis (lpgi) is involved in the pain modulation, too. the aim of the current study was to investigate the involvement of the membr...

Histamine as a neurotransmitter participates in modulation of pain transmission within the central nervous system. Exogenous histamine administered intracerebroventricularly (icv) as well as endogenous histamine, after blockage of its catabolism by histamine N-methyltransferase (HNMT) inhibitors, which leads to an increase in endogenous histamine concentrations, produce an antinociceptive effec...

BACKGROUND Spinal serotonin (5-HT) receptors 3 (5-HT3R) and 7 (5-HT7R) are differentially involved in facilitatory or inhibitory descending modulation, respectively. Electrophysiological studies of the spinal cord have demonstrated that 5-HT3R is involved in nociception induced by intraplantar injection of formalin, but not carrageenan. In addition, depletion of spinal serotonin has been shown ...

Formalin as a chemical noxious stimulus evokes a biphasic pain that its second phase as a chronic inflammatory pain is similar to clinical pain. In this study, we used 40 NMRI male rats (250-300 g), and experiments were carried out considering ethical rules. Experiments were performed in normal and morphine addicted rats, the addiction was induced by Leung method. Behaviors of flinching and lic...