objectives: crocin, a constituent of saffron and yellow gardenia, possesses anti-nociceptive effects. in the present study, we investigated the effects of intra-fourth ventricle injection of crocin in a rat model of orofacial pain. the contribution of opioid system was assessed using intra-fourth ventricle injection of naloxone, an opioid receptor antagonist. materials and methods: a guide cann...

Tolerance to the analgesic effect of morphine is a major clinical problem which can be managed by co-administration of another drug. This study investigated the ability of propranolol to potentiate the antinociceptive action of morphine and the possible mechanisms underlying this effect. Antinociception was assessed in three nociceptive tests (thermal, hot plate), (visceral, acetic acid), and (...

The response to painful stimulation depends not only on peripheral nociceptive input but also on the cognitive and affective context in which pain occurs. One contextual variable that affects the neural and behavioral response to nociceptive stimulation is the degree to which pain is perceived to be controllable. Previous studies indicate that perceived controllability affects pain tolerance, l...

introduction: nowadays opioids are gaining acceptance for the management of moderate to severe and chronic pain. in addition, a number of studies have shown that plasma levels of β-endorphin (βep) in exercise trained are higher than sedentary rats. in our study we assume that exercise training can reduce pain after withdrawal syndrome in morphine-dependent rats. methods: male wistar rats (250±2...

there are several reports that adenosine and carbamazepine have pharmacodynamic interaction. i n this study the antinociceptive interaction o f these two agents was evaluated in mice by the hot plate test. agents were injected intraperitoneally. 0.2 and 0.4 mg/kg doses of r-phenylisopropyladenosine (r-pia) substantially showed antinociceptive effects. carbamazepine had antinociceptive actions e...

It is widely assumed that distraction reduces pain. Similarly, it is assumed that pain distracts from concurrent, unrelated cognitive processing, reducing performance on difficult tasks. Taken together, these assumptions suggest pain processing and cognitive function engage an overlapping set of domain-general, capacity-limited mental resources. However, experimental tests of this proposal have...

Pain perception arises from a complex interaction between a nociceptive stimulus and different emotional and cognitive factors, which appear to be mediated by both automatic and controlled systems. Previous evidence has shown that whereas conscious processing of unpleasant stimuli enhances pain perception, emotional influences on pain under unaware conditions are much less known. The aim of the...

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...

Pain is a complex process in the central nervous system (CNS). Several factors can alter the pain threshold and insulin is one of them which is produced by the beta cells of pancreas and capable of crossing blood-brain barrier. The aim of this study was to evaluate the effects of intra-cerebroventricular (ICV) injection of insulin on the pain response to formalin in short-term induced diabetic ...

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...