Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The purpose of this study was to examine the behavioural responses of infants to pain stimuli across different developmental ages. Eighty infants were included in this cross-sectional design. Four subsamples of 20 infants each included: (1) premature infants between 32 and 34 weeks gestational age undergoing heel-stick procedure; (2) full-term infants receiving intramuscular vitamin K injection; (3) 2-month-old infants receiving subcutaneous injection for immunisation against DPT; and (4) 4-month-old infants receiving subcutaneous injection for immunisation against DPT. Audio and video recordings were made for 15 sec from stimulus. Cry analysis was conducted on the first full expiratory cry by FFT with time and frequency measures. Facial action was coded using the Neonatal Facial Action Coding System (NFCS). Results from multivariate analysis showed that premature infants were different from older infants, that full-term newborns were different from others, but that 2- and 4-month-olds were similar. The specific variables contributing to the significance were higher pitched cries and more horizontal mouth stretch in the premature group and more taut tongue in the full-term newborns. The results imply that the premature infant has the basis for communicating pain via facial actions but that these are not well developed. The full-term newborn is better equipped to interact with his caretakers and express his distress through specific facial actions. The cries of the premature infant, however, have more of the characteristics that are arousing to the listener which serve to alert the caregiver of the state of distress from pain.
Pain 1993 Feb
PMID:Developmental changes in pain expression in premature, full-term, two- and four-month-old infants. 845 68

We studied the effect of cholecystokinin (CCK-8) and yohimbine-alpha-2-adrenoreceptor antagonist administered locally into lateral reticular formation (LRF) on the bioelectrical response to the pain stimulation. The experiments were carried out on 8 conscious rabbits with bilaterally implanted electrodes into: motor-sensory cortex, ventro-postero-lateral thalamic nuclei, hippocampus and LRF. Nociceptive stimulation was performed by means of electrical pulses applied to the front paw. Bioelectrical activity (BA) of the chosen brain structures was analysed by means of spectral analysis (FFT) and directed transfer function (DTF). The results of our study may suggest that supraspinal administration of CCK-8 together with yohimbine have inhibitory effect on nociceptive transmission.
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PMID:Influence of CCK-8 and yohimbine on supraspinal modulation of nociceptive process. 878 81

Axial rotation of the trunk is commonly associated with back injury and pain. However, the behaviour of trunk muscles in axial rotation is poorly understood. The objective of this study was to measure spectral parameters from the EMG of erector spinae at T10 and L3 levels, latissimus dorsi, external and internal oblique, rectus abdominis and pectoralis major muscles bilaterally in a standardized repeatable axial rotation at 60% MVC to fatigue. Twelve young and healthy subjects were recruited after screening for musculoskeletal disorders. Surface electrodes were applied to the named seven trunk muscles bilaterally. Subjects were seated in the device called Axial Rotation Tester and stabilized such that they could rotate only their thoracolumbar spine. Other motions were prevented. Subjects held 60% of their MVC for a period of 2 min. Samples (2.1 s) were obtained at every 10 s interval at a sampling frequency of 1 KHz. Samples were subjected to FFT analysis. The total power and the median frequencies were analyzed. The median frequency for different muscles were different (p < 0.001). The slopes of decline of the median frequencies of the agonists were different for different muscles (p < 0.001). This differential fatiguing rate could conceivably create a force imbalance potentiating back injury.
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PMID:Spectral parameters of trunk muscles during fatiguing isometric axial rotation in neutral posture. 977 99

Afferent fibers from gastrointestinal tract outnumber efferents ten times in vagal nerves. Modifying the afferent input makes possible to change discharge of vagal efferents affecting gastrointestinal functions in process known as neuromodulation (NM). Lately it has been used in the treatment of pain and hyperactive neurogenic bladder in urology. MC induced NM may therefore provide a concurrent to pharmacology tool, in treatment of gastrointestinal disorders. The aim of this study was to investigate the effects of long term neuromodulation procedure with use of MC on gastric motility, secretion and weight control in conscious rats. Experiments were performed on 30 Wistar male rats (250-350 g) divided in two groups: sham operated and microsurgically implanted with MC on left vagal nerve below diaphragm. Following stimulation parameters were used: frequency of 0.5-30 Hz, amplitude of 0.55 V, impulse duration of 10 ms in monophasic fashion. In both groups food intake and body weight were measured through the period of 2 weeks after recovery period. Then gastric fistula was implanted in gastric antrum and fasted gastric motility recorded with use of PowerLab system (Australia). Gastric emptying and secretion were also tested with use of phenol red and automatic titration methods. On the daily basis glucose level with standard test and leptin after MC implantation were measured. Recording of vagal activity in fasted rats showed burst of action potentials about 5 +/- 2.5 in period of 5000 sec, each burst with spike frequency up to 35 Hz. Food (5 ml of Intralipid--intragastrically) almost doubled amount of bursts to 12 +/- 5 in period of 5000 sec with increase in frequency at spike up to 50 Hz. MC induced vagal activity showed continuous spike activity similar to fed pattern. MC induced NM decreases daily food intake by 6% (33.6 +/- 4.8 vs control 35.5 +/- 4.8 g, p < 0.01). Body weight gain in rats before MC implantation decreased by 20% within 2 weeks after recovery (34.8 +/- 9.08 vs control 23.56 +/- 4.15 g). Fasting control glucose level also decreased of 5.5% (93.15 +/- 9.3 vs control 98.5 +/- 11.2 mg%, p < 0.05). Frequency of gastric contractions did not change significantly in MC versus control but amplitude of contractions increased of about 66.7% (2.0 +/- 0.8 vs 1.17 +/- 0.52) at the dominant frequency 0.08 Hz range and about 71.5% (1.17 +/- 0.35 vs 0.68 +/- 0.47, p < 0.05) at the frequency 0.12 Hz. in FFT analysis PowerLab (chart v = 4.01). BAO decreased by 29.25% without H+ concentration changes (0.2 +/- 0.14 vs 0.14 +/- 0.12 mmol/30 min, p < 0.05) but MAO did not change in MC rats (0.37 +/- 0.25 vs 0.42 +/- 0.28 mmol/30 min, p 0.05). Gastric emptying of isotonic solution increased by 10% (90.46 +/- 5.34 vs 80.39 +/- 9.95) percent of marker passing to duodenum/5 min, p < 0.0001). Our results suggest that MC induced NM affect brain-gut axis via influencing metabolic and gastric function and decreases body weight.
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PMID:Effects of continuous microchip (MC) vagal neuromodulation on gastrointestinal function in rats. 1178 68

A number of brain regions are associated with the subjective experience of pain. This study adds to our understanding of the neural mechanisms involved in pain by considering the relation between cortical oscillations in response to pain, with and without hypnosis and hypnotic analgesia, and the subjective experience of pain. Thirty-three subjects' neural responses (EEG) were measured during the 40-540 ms period following phasic electrical stimulations to the right hand, under control and hypnosis conditions. Resultant FFT amplitudes for frequencies ranging from 8 to 100 Hz were computed. These were grouped into 7 scalp topographies, and for each frequency, relations between these topographies and pain ratings, performance and stimulus intensity measures were assessed. Gamma activity (32-100 Hz) over prefrontal scalp sites predicted subject pain ratings in the control condition (r=0.50, P=0.004), and no other frequency/topography combination did. This relation was present in both high and low hypnotisable subjects and was independent of performance and stimulus intensity measures. This relation was unchanged by hypnosis in the low hypnotisable subjects but was not present in the highs during hypnosis, suggesting that hypnosis interferes with this pain/gamma relation. This study provides evidence for the role of gamma oscillations in the subjective experience of pain. Further, it is in keeping with the view that hypnosis involves the dissociation of prefrontal cortex from other neural functions.
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PMID:Pain perception, hypnosis and 40 Hz oscillations. 1243 87

Tramadol, an analgesic with mean potency one tenth that of morphine is used regularly for the treatment of chronic and postoperative pain. Previous reports have indicated that tramadol may induce seizure activity when given together with a selective serotonin reuptake inhibitor (SSRI). Therefore, its major mode of action may be questioned which purportedly is due to binding with the opioid receptor and partly due to the inhibition of monoamine reuptake. We therefore set out to study its potential in inducing seizure activity and to quantify its effect on EEG-power spectra and on the central modulation of sensory afferents in awake and trained dogs (n=7). In order to demonstrate if opioid receptors mediated these effects, incremental doses of tramadol were given which was followed by naloxone for possible reversal. After a wash-out period the same animals were exposed to graded doses of alfentanil, a pure mu-receptor agonist. Again this was followed by the opioid antagonist naloxone for reversal.The electroencephalogram (EEG) and the event-related evoked potentials (SEP) were used to demonstrate possible excitatory effects. In order to derive the SEP the front paw was stimulated electrically (Digi Stim II trade mark ) while the evoked potentials were picked up contralaterally from the somatosensory cortex using stick-on electrodes. 256 sweeps were averaged (Lifescan) and the peak-to-peak amplitude was measured to demonstrate CNS excitation compared to control (%). Additionally, the raw electroencephalogram was viewed for epileptogenic changes and its power computed into the various power bands alpha, beta, delta und theta using FFT over a time epoch of 60 s. Following control, graded doses of either tramadol (2-5-10 mg/kg i.v.) or alfentanil (10-30-60 microg/kg i.v.) were given every 15 min while the EEG and the SEP were recorded. Thereafter naloxone (20 microg/kg i.v.) was injected for reversal. Tramadol did not suppress the amplitude of the SEP at any dose. High doses (>5 mg/kg i.v.) resulted in an increase (+100%) of the amplitude of the evoked potential. This was accompanied by short-term muscle fibrillations, and a short-term spike-and-wave activity in the EEG followed by a long-lasting theta-dominance. These effects could not be reversed by naloxone. In contrast to tramadol, alfentanil induced a dose-related depression of amplitude in the SEP with a maximum of 82% suggesting a depressive effect of modulation of afferents in the sensory cortex. This effect was fully naloxone reversible and was followed by a rebound in amplitude of the SEP together with an increase in fast beta-waves in the EEG. Tramadol very little mediates its central action via the mu-opioid receptor as the present effects were not naloxone reversible. Consistent with the results is the very low affinity of tramadol to the opioid receptor which is several thousand times less than that of morphine. Most likely, inhibition of central norepinephrine and serotonin reuptake as well as the reduction in 5-HT-turnover may contribute to the effects of tramadol. Due to the monoamine reuptake inhibition an increase in transmission may result, triggering off excitatory phenomena with spike-and-wave activity in the CNS. Such excitatory effects, however, may only be seen when tramadol is used in doses exceeding the therapeutic range.
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PMID:[The opioid tramadol demonstrates excitatory properties of non-opioid character--a preclinical study using alfentanil as a comparison]. 1279 88