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Pain Stimulus (pain + stimulus)

Distribution by Scientific Domains

Medical Sciences	28%

Selected Abstracts

Salivary melatonin response to acute pain stimuli

JOURNAL OF PINEAL RESEARCH, Issue 4 2001
F.A. Nelson
Evidence for a relationship between melatonin, nociception, and analgesia in humans is based on data that are only linked by association and simultaneous occurrence. Studies have reported inverse correlation of the circadian melatonin rhythm with nociception latency and enhancement of opioid analgesia by simultaneous administration of melatonin in animals. This study examines the response of salivary melatonin to acute pain stimuli in 18 healthy subjects ranging in age from 19 to 50 years. A biphasic melatonin response following an acute pain stimulus of 36 V was observed, F(8, 8)=17.839, P<0.001. Within 5 min of the stimulus, melatonin decreased and reached a plateau of 36 pg/mL below baseline by 20 min. This decrease was followed by an increase of 5 pg/mL. Melatonin levels subsequently decreased until they had reached levels similar to those anticipated for the time of day and did not vary thereafter. The magnitude of the melatonin response was not related to age or gender. There was no association between voltage and magnitude of the melatonin responses observed at 15 min (r=0.185, P=0.51) or at 30 min (r=0.468, P=0.09). This study provides the first evidence of melatonin utilization and subsequent pineal gland synthesis following acute pain episodes in humans. [source]

Chest pain is inversely associated with blood pressure during exercise among individuals being assessed for coronary heart disease

PSYCHOPHYSIOLOGY, Issue 2 2007
Blaine Ditto
Abstract Acute and chronic increases in blood pressure have been related to decreases in pain perception. This phenomenon has been studied primarily using acute experimental pain stimuli. To extend the literature to naturalistic pain and in particular the problem of silent cardiac ischemia, this study examined the relationship between blood pressure and chest pain during exercise stress testing. Nine hundred seven (425 men, 482 women) individuals undergoing exercise stress testing for diagnosis of possible myocardial ischemia completed the McGill Pain Questionnaire (MPQ) immediately afterward and other questionnaires before and after testing. Blood pressure was measured before, during, and after exercise. Systolic blood pressure at the end of exercise was inversely related to a number of measures of pain such as total score on the MPQ. The relationship could not be explained by individual differences in exercise duration, medication use, sex, or other measured variable. In sum, the inverse relationship between blood pressure and sensitivity to pain that has been observed in other populations in experimental and naturalistic conditions was observed for chest pain during exercise. Blood pressure may contribute to episodes of silent ischemia. [source]

CNS response to a thermal stressor in human volunteers and rats may predict the clinical utility of analgesics

DRUG DEVELOPMENT RESEARCH, Issue 1 2007
David Borsook
Abstract fMRI was used to test the hypothesis that global brain activation following a stressor (a thermal stimulus) that activates multiple brain circuits in healthy subjects can predict which drugs have higher potential for clinical utility for neuropathic pain. The rationale is that a drug will modulate multiple neural circuits that are activated by the system-specific stressor (e.g., pain). In neuropathic pain, some brain circuits have altered function, but most brain systems are "normal." Thus, the manner in which a drug effect on neural circuits is modulated by the stressor may provide insight into the clinical utility based on the readout of brain activation in response to the stimulus. Six drugs with known clinical efficacy (or lack thereof) in treating neuropathic pain were selected and the CNS response to each drug in the presence or absence of a pain stimulus was examined. The present results suggest that it is possible to identify potentially effective drugs based on patterns of brain activation in healthy human subjects and indicate that CNS activity is a more sensitive measure of drug action than standard psychophysical measures of pain intensity. This approach was repeated in rats and showed that a similar fMRI paradigm segregates these drugs in a similar manner suggesting a potential "translational tool" in evaluating drug efficacy for neuropathic pain. The sensitivity of this paradigm using fMRI allows clinical screening in small groups of healthy subjects, suggesting it could become a useful tool for drug development as well as for elucidating the mechanisms of neuropathic disease and therapy. Drug Dev. Res. 68:23,41, 2007. © 2007 Wiley-Liss, Inc. [source]

Salivary melatonin response to acute pain stimuli

Prediction of post-operative pain by an electrical pain stimulus

ACTA ANAESTHESIOLOGICA SCANDINAVICA, Issue 5 2007
P. R. Nielsen
Background:, Treatment of post-operative pain is still a significant problem. Recently, interest has focused on pre-operative identification of patients who may experience severe post-operative pain in order to offer a more aggressive analgesic treatment. The nociceptive stimulation methods have included heat injury and pressure algometry. A simple method, Pain Matcher® (PM), using electrical stimulation, is validated for pain assessment, but has not been evaluated as a tool for prediction of post-operative pain. Our aim was to assess the predictive value of pre-caesarean section pain threshold on intensity of post-caesarean section pain using the PM. Patients and methods:, Thirty-nine healthy women scheduled for elective caesarean section were studied. The anaesthetic/analgesic procedures included spinal anaesthesia, paracetamol, diclofenac, controlled-release (CR) oxycodone and morphine on request. Pre-operatively, the sensory and pain thresholds were measured using the PM. Post-operatively, a midwife, blinded for pre-caesarean pain threshold assessments, assessed the pain at rest and during mobilization every 12 h for 2 days. Consumption of analgesics was also recorded. Results:, Pre-operative pain threshold correlated significantly with post-caesarean pain score (VAS) at rest and mobilization: [Spearman's rho =,0.65 (,0.30 to ,0.75), P < 0.01] and [Spearman's rho =,0.52 (,0.23 to ,0.72), P < 0.01], respectively. There was no significant correlation between pre-operative PM assessment of sensory threshold and post-operative pain. Conclusion:, Electrical pain threshold before caesarean section seems to predict the intensity of post-operative pain. This method may be used as a screening tool to identify patients at high risk of post-operative pain. [source]

Synthesis and Pharmacological Evaluation of N -(Dimethylamino)ethyl Derivatives of Benzo- and Pyridopyridazinones

ARCHIV DER PHARMAZIE, Issue 1 2009
Wanda Pakulska
Abstract New N -(dimethylamino)ethyl derivatives of phthalazinones and pyridopyridazinones 7, 9 were synthesized and assayed as potential analgesic agents in the hot-plate, tail-flick, and writhing tests. Pharmacological assay demonstrated that eight (in ten) of the newly synthesized compounds showed antinociceptive activity. Especially, 2-[2-(dimethylamino)ethyl]-4-phenyl-2H -phthalazin-1-one 7a showed remarkably higher antinociceptive activity in all tests. This is connected with influence on supraspinal, spinal, and peripheral structures. The decreased sensitivity to the pain stimulus in the hot-plate was higher than that of metamizole. [source]