Pain is a physiological and adaptive process which occurs to protect organisms from tissue damage and extended injury. Pain sensation beyond injury, however, is a pathological process which is poorly understood. Experimental models of neuropathic pain demonstrate that reactive astrocytes contribute to reduced nociceptive thresholds. Astrocytes release "gliotransmitters" such as D-serine, glutam...

Noradrenaline (NA), a key neurotransmitter of the endogenous pain inhibitory system, acutely inhibits nociceptive transmission (including that mediated by substance P), potentiates opioid analgesia, and underlies part of the antinociceptive effects of the widely prescribed tricyclic antidepressants. Lesions of noradrenergic neurons, however, result in either normal or reduced pain behavior and ...

To understand characteristics of the pain system in the elderly, we investigated the electrophysiological properties of nociceptive neurons in the lumbar spinal dorsal horn of aged (29-34-mo old) and adult (7-13-mo old) rats. The responses of nociceptive neurons to noxious thermal stimulation, as well as the spontaneous firing rate, were significantly higher in the aged as compared with adult r...

Context: Neuropathic pain is a common and disabling complication. To develop a better treatment of the neuropathic pain, a comprehensive understanding is essential. In this paper, we review pathophysiological principles of neuropathic pain, focusing on synaptic plasticity and long-term potentiation (LTP) in the nociceptive circuits. Finally, the role of glial cells on the synaptic plasticity in...

Monosodium glutamate (MSG) is a widely used food additive. Although it is generally considered safe, some questions regarding the impact of its use on general health have arisen. Several reports correlate MSG consumption with a series of unwanted reactions, including headaches and mechanical sensitivity in pericranial muscles. Endogenous glutamate plays a significant role in nociceptive process...

Cannabinoids produce anti-nociceptive and anti-hyperalgesic effects in acute, inflammatory and neuropathic pain models. The current study investigated the role of cannabinoid (CB1 and CB2) receptors in modulating formalin-induced nociceptive behavior and mechanical allodynia in the rat. Rats received subcutaneous plantar injections of 5% formalin in the hind paws. Licking, biting and paw flinch...

We examined the effects of adenosine 5'-triphosphate (ATP) and its analogues administered intracerebroventricularly on nociceptive thresholds in rats. Intracerebroventricular (i.c.v.) administration of ATP (10 and 100 nmol/rat), alpha,beta-methylene-ATP (1-30 nmol/rat) and 2', 3'-O-(4-benzoylbenzoyl)-ATP (1-30 nmol/rat) dose-dependently elevated the mechanical nociceptive threshold in the paw p...

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 ...

There is now ample evidence that blind individuals outperform sighted individuals in various tasks involving the non-visual senses. In line with these results, we recently showed that visual deprivation from birth leads to an increased sensitivity to pain. As many studies have shown that congenitally and late blind individuals show differences in their degree of compensatory plasticity, we here...

Hyperalgesia is one of the debilitating complications of diabetes. The thermal allodynia and hyperalgesia in diabetic mice may be due to the hyperactivity of C-fiber in the spinal cord. Transient receptor potential vanilloid type 1 (TRPV1) present in spinal cord and activation of C-fibre may involve in hyperalgesia in diabetic mice. Desipramine is one of the tricyclic antidepressants, effective...