The present study investigated the role of calcitonin gene-related peptide (CGRP) in the modulation of nociception in periaqueductal grey (PAG) of rats. Hindpaw withdrawal latencies (HWLs) were tested by hot-plate and Randall Selitto tests. The HWLs to thermal and mechanical stimulation increased significantly after intra-PAG administration of 0.26 or 0.13 nmol of CGRP, but not 0.026 nmol of CG...

We hypothesized that TRPV4, a member of the transient receptor family of ion channels, functions as a sensory transducer for osmotic stimulus-induced nociception. We found that, as expected for a transducer molecule, TRPV4 protein is transported in sensory nerve distally toward the peripheral nerve endings. In vivo single-fiber recordings in rat showed that hypotonic solution activated 54% of C...

The effects of various sodium channel blocking agents on acute thermal and mechanical nociception, as assessed using the plantar and tail pressure tests, respectively, were compared with the effects of morphine. The drugs used were mexiletine, lidocaine, carbamazepine, phenytoin, eperisone, tolperisone, and zonisamide. The sodium channel blocking agents exhibited a rather preferential elevation...

Pains arising from the viscera constitute a large portion of clinically treated pains. They are characterized by poor localization; immobility with tonic increases in muscle tone; and vigorous but nonspecific changes in autonomic function, such as changes in respiration, heart rate, and blood pressure. Tissue-damaging stimuli do not reliably produce visceral pain, so the study of visceral nocic...

Microglial cells appear to play a vital role in the initiation of certain neuropathic pain states. In order to initiate neuropathic pain, microglia need to be activated. Microglia activation in the spinal cord involves both hypertrophy as well as hyperplasia, progressing through a hypertrophic morphology, with thickened and retracted processes (observed within the first 24 hours after nerve inj...

Like most reviews on the pathophysiology of pain this lecture will mainly consider the physiology of nociceptiono Nociception like other sensory modalities is subserved by a specific array of nervous connexions which have been known in broad lines for many yearso A number ofneurosurgical operating procedures (cordotomy, tractotomy .oo) were based on this' knowledge. In recent years owing to maj...

Capsaicin, the pungent ingredient of the hot chili pepper, is known to act on the transient receptor potential cation channel vanilloid subfamily member 1 (TRPV1). TRPV1 is involved in somatic and visceral peripheral inflammation, in the modulation of nociceptive inputs to spinal cord and brain stem centers, as well as the integration of diverse painful stimuli. In this review, we first describ...

The study of pain in awake animals raises ethical, philosophical, and technical problems. We review the ethical standards for studying pain in animals and emphasize that there are scientific as well as moral reasons for keeping to them. Philosophically, there is the problem that pain cannot be monitored directly in animals but can only be estimated by examining their responses to nociceptive st...

described multiple potential factors whereby smoking may contribute to pain. Smith (5) has postulated a potential novel mechanism whereby smoking may contribute to inflammatory pain via its inhibitory actions on an enzyme known as leukotriene A4 hydrolase (LTA4H), --an action on the peptidase site of LTA4H revealed by Snelgrove et al(6). Epidemiologic studies have reported an association betwee...

In addition to its effect on reproductive organs, estrogen exhibits complex effects on brain structure, function and behavior. In this regard, the influence of gonadal hormones especially estrogens on nociception has recently been accepted. Soybean is known as an important phytoestrogen containing plant that is used as an alternative for estrogen replacement therapy. In this study, the influenc...