Neuroimaging and neurophysiological studies have shown that nociceptive stimuli elicit responses in an extensive cortical network including somatosensory, insular and cingulate areas, as well as frontal and parietal areas. This network, often referred to as the "pain matrix", is viewed as representing the activity by which the intensity and unpleasantness of the perception elicited by a nocicep...

Opioids modulate the affective component of pain and in vivo data indicate that opioids induce activation changes in the rostral ACC, insula and other brain areas. Hence, opioidergic release is to be expected in these brain regions following experimental pain stimulation. We examined healthy volunteers during heat pain and control subjects during rest using [18F]fluorodiprenorphine-PET. Pain st...

Cerebral processes contribute to pain beyond the level of nociceptive input and mediate psychological and behavioural influences. However, cerebral contributions beyond nociception are not yet well characterized, leading to a predominant focus on nociception when studying pain and developing interventions. Here we use functional magnetic resonance imaging combined with machine learning to devel...

Background and Aims: It is well-recognized that endogenous opioidergic system plays an important role in pain sensitivity, pain perception, and response to some stressing situations. The present study examined the probable role of endogenous opioidergic system in effects of food deprivation on formalin-induced nociceptive behaviors in male and female rats. Methods: To make short-term food d...

Recent studies have shown that intracerebroventricular administration of cimetidine (CIM) induces anti-nociceptive and anti–inflammatory effects in rats. However, the underlying mechanism of CIM effect has not been determined yet. This study was planned to determine the anti-nociceptive effect of CIM (50 mg/kg, i.p.) in male mice (25-30 g, n = 80) using tail flick test. Also, the role of ATP-se...

introduction: formalin injection induces nociceptive bahaviour in phase i and ii, with a quiescent phase between them. while active inhibitory mechanisms are proposed to be responsible for initiation of interphase, the exact mechanisms which lead to termination of nociceptive response in phase ii are not clear yet. phase ii is a consequence of peripheral and central sensitization processes, whi...

cuminum cyminum linn. (umbelliferae) is a plant, which has been used as a toothache remedy in folk medicine of iran. in this study, the potential anti-nociceptive and anti-inflammatory activities of the fruit essential oil of c. cyminum has been evaluated in chemical (formalin test) and thermal (tail-flick test) models of nociception and formalin model of acute inflammation in rats and mice. th...

The gate control theory proposed that the nociceptive sensory information transmitted to the brain relies on an interplay between the inputs from nociceptive and non-nociceptive primary afferent fibers. Both inputs are normally under strong inhibitory control in the spinal cord. Under healthy conditions, presynaptic inhibition activated by non-nociceptive fibers modulates the afferent input fro...