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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Severe skin pain lasting one or two months occurred in 8 of 210 patients treated with PUVA. The pain started 4--8 weeks after the initial dose, mostly about one week after discontinuation of the treatment. It was a prickling, burning pain, usually coming in bouts and confined to limited areas "deep under the skin". In some respects the pain was related to itching, but the patients could easily distinguish between the two sensations. A variety of drugs was tried, but none had any noteworthy effect on this peculiar pain.
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PMID:Severe skin pain after PUVA treatment. 9 76

A study was made of the effect of chlorpromazine on the multiplication of late slow component of evoked potential to the flash-light (1 sec.) in experiments on nonanesthetized rabbits with electrodes chronically implanted in different brain structures. Electro-skin pain stimulation of the pore was applied simultaneously in some experiments. Chlorpromazine was found to decrease the multiplication of the late slow component to the flash-light alone, and to double this component in response to light when it was combined with pain stimulation. A supposition was made on the role of adrenergic structures in the formation of the acceptor of the action results of a defensive character, serving as one of the most important mechanisms of the functional system.
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PMID:[Multiplication of the late slow fluctuation of induced potential to light under conditions of aminazin administration]. 122 72

The effect of vibratory stimulation on experimental pain of the skin overlying the right and left extensor carpi radialis longus muscle induced by electrical stimulation was studied in 16 healthy subjects and in 18 patients suffering from chronic epicondylalgia of the right elbow. In the healthy subjects there were no side differences whereas in the patients, the skin pain threshold over the painful right muscle was lower than that on the left unaffected side under resting conditions. After vibratory stimulation, the skin pain threshold increased bilaterally by 1.1-1.6 times the pre-stimulation threshold in the healthy subjects and by 1.2-2.3 times this threshold in the patients. In 8 of the healthy subjects there was an increase in peripheral blood flow during stimulation and in 8 there was a small decrease. In 13 patients the change in pain threshold was seen in phase with the local increase and peripheral decrease in peripheral blood flow. In all individuals, the pain thresholds were regained within 45 min of cessation of stimulation. This was in contrast to the general subjective pain in the patients; 12 patients reported that the relief of pain lasted for a period of 1-7 hours.
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PMID:Effect of vibratory stimulation on experimental and clinical pain. 326 33

The evolution of aerobic organisms required the development of oxygen sensors so the organism could avoid anoxic environments. In man these oxygen sensors are known as pain receptors. The skin pain receptor includes the epidermis and the dermal papilla with its capillary and terminal nerve. A pain stimulus such as a pin prick occludes blood flow into the papilla. The epidermal cells consume enough residual oxygen to produce a fall in oxygen tension at the nerve ending sufficient to cause the nerve to fire. The maximum time required for the oxygen drop is 0.04 seconds.
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PMID:Pain: evolutionary background and primary stimulus. 720 81

Our objective was to determine if local anesthesia reduces pain after a laparoscopy. Eighty women were assigned randomly 10 ml of 0.5% bupivacaine or 0.9% saline flushed over the peritoneal folds and into the abdominal wall after laparoscopy under general anesthesia. Pain scores from the deep abdomen, skin, shoulder, and back were collected 30 min, 2 h, 4 h, and the day following laparoscopy. Pain scores also were correlated with patients' height, weight, operative findings, surgical technique and procedure, and volume of gas insufflated into the abdomen. Bupivacaine has a small effect on abdominal and skin pain 2 h after surgery (p = 0.01) but has no effect on shoulder or back discomfort. Women who have been sterilized, have not had previous abdominal surgery, or have evidence of old pelvic inflammation report more postoperative backache and deep abdominal pain but no greater skin or shoulder discomfort. Weight, height, whether the abdominal wall was picked up, and the volume of gas used to insufflate the abdomen are independent of all postoperative pain scores. Local anaesthetic instilled down the laparoscopy trocar reduces skin discomfort 2 h after surgery, but this beneficial effect is small compared with other factors influencing pain after laparoscopy.
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PMID:Pain after laparoscopy: an observational study and a randomized trial of local anesthetic. 1015 Mar 92

Results were obtained from comparative studies of skin pain sensitivity (pain thresholds) using focused ultrasound in 51 healthy men and 101 patients with neurasthenia. Neurasthenia is a natural "model" of chronic psychoemotional stress, and patients showed a reduction in the pain threshold which was not accompanied by a reduction in the threshold of sensitivity to tactile stimulation. A reduction in the pain threshold, reflecting a weakening of central descending tonic inhibition, was probably due to a reduction in the activity of the brain's opioid system during long-term psychoemotional stress. Analysis of the relationships between the pain sensitivity threshold and pain syndromes suggests a role for changes in the nociception system in chronic psychoemotional stress, as part of the mechanism of pain formation.
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PMID:Pain sensitivity in chronic psychoemotional stress in humans. 1049 47

The present study compared capsaicin-induced muscle and skin pain in humans. Twelve healthy subjects received, in a randomised, balanced order, 3 intramuscular (i.m.) injections into the brachioradial muscle: capsaicin 100 microg/1 ml, capsaicin 100 microg/20 microl or 1 ml solvent (Tween 80), and one intradermal injection (i.d.): capsaicin 100 microg/20 microl. Local and referred pain intensities and areas were assessed from 0 to 60 min after injection. Intradermal capsaicin produced more intense local pain than i.m. capsaicin in the first min (skin: 68+/-6, muscle: 51+/-6 mm VASxmin, P<0.05). In contrast, the local pain offset was later (muscle: 38+/-5, skin: 23+/-5 min, P<0.05) and referred pain was more frequent (muscle: 9/12, skin: 1/12 subjects, P<0.01) following i.m. capsaicin compared with i.d. capsaicin. Capsaicin (1 ml) produced significantly more pain than 20 microl i.m. (pain in the first min: 1 ml: 71+/-6, 20 microl: 51+/-6 VASxmin, P<0.05, offset: 1 ml: 50+/-4, 20 microl: 38+/-5 min, P<0.05). The different local and referred pain following identical noxious stimulation of muscle and skin indicates that the neurophysiological mechanisms underlying skin and muscle pain differs. The model with identical noxious stimulation of muscle and skin may be suitable for the study of differences in deep and superficial pain as seen in the clinic.
Pain 2000 Feb
PMID:Intramuscular and intradermal injection of capsaicin: a comparison of local and referred pain. 1066 47

Cutaneous applications are gaining popularity in the treatment of cutaneous pain and of painful disorders in joints and muscle. The low pH-pain model in human skin has previously been able to demonstrate the effects of NSAIDs in dose-dependent manner and to establish time-effect relationships. We examined the analgesic action of ibuprofen after cutaneous application and compared the effects with oral administration. The two studies (with n = 12 subjects each) were performed in a double-blind, randomized fashion with a 1-week cross-over interval. In study 1 volunteers received intradermal infusions with phosphate buffered saline solution of pH 5.2 and received either 800 mg ibuprofen per os and topical placebo, or 4 g of a 5% commercial ibuprofen gel topically applied and oral placebo capsules, respectively. In study 2 the same protocol was applied with painful intramuscular infusion of stronger, isotonic phosphate buffer (pH 5.2). The flow rate of the pH-infusion was individually adjusted to induce pain with a magnitude of 20% on a visual analogue scale (ranging from 'no' (0%) to 'unbearable pain' (100%)). Ibuprofen (S-, R-) plasma levels after oral administrations were measured with HPLC, and after topical applications, by gas chromatography combined with mass spectroscopy to determine plasma levels in the range of ng/ml. In the cutaneous model pain ratings decreased to zero after topical verum gel within 45 min of the observation period of 55 min. Pain reduction after peroral ibuprofen was of the same magnitude, but was achieved within only 30 min. In the muscle model, the commercial ibuprofen gel did not reduce the pain in the acidic muscle. The peroral ibuprofen was less effective in the muscle compared to the skin pain model, although there was a significant progressive pain reduction within 55 min. Reasons for the differential susceptibility of cutaneous vs muscular acidosis pain to ibuprofen remain to be established.
Eur J Pain 2000
PMID:Plasma levels after peroral and topical ibuprofen and effects upon low pH-induced cutaneous and muscle pain. 1095

The pathophysiology of many orofacial pain syndromes is still unclear. We investigated the effect of tonic muscle and skin pain on the excitability of the trigeminal motor pathways using transcranial magnetic stimulation (TMS). Motor evoked potentials (MEPs) were recorded in the masseter surface electromyogram (EMG). Magnetic pulses were delivered with a large coil at intensities 1.1 and 1.5 times the motor threshold, and for each intensity, MEPs were recorded at three different clenching levels: 15, 30 and 45% of maximum voluntary contraction (MVC). Baseline, pain and post-baseline recordings were compared in two sessions. Firstly, muscle pain was induced by infusion of hypertonic saline (5.8%) into the left masseter. Secondly, skin pain was induced by topical application of capsaicin (5%) on the left cheek. Muscle and skin pain did not induce significant effects on the amplitude or latency of the MEPs (ANOVAs: P>0.50). In both sessions, the amplitude of the MEPs increased with the increase of the clenching level and stimulus intensity (P<0.0001; P<0.005) whereas the latency was not significantly changed (P>0.05; P=0.11). Muscle pain was associated with an increase in the pre-stimulus EMG activity on the non-painful side compared with baseline (P<0.01), which could be due to compensatory changes in the activation of the painful muscle. The need for voluntary contraction to evoke MEPs in the masseter muscles and compensatory mechanisms both at the brainstem and cortical level might explain the lack of detectable modulation of MEPs. Nonetheless, the present findings did not support the so-called 'vicious cycle' between pain - central hyperexcitability - muscle hyperactivity.
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PMID:Effect of experimental pain from trigeminal muscle and skin on motor cortex excitability in humans. 1105 91

Cutaneous laser stimulation activates predominantly the A-delta and C mechano-heat nociceptors. Applied to the perioral region, low intensity CO(2)-laser pulses evoke reproducible trigeminal cortical evoked potentials (LEPs). High intensity CO(2)-laser stimuli induce a reflex response in the contracted jaw-closing muscle, the so-called laser silent period (LSP). Both LEPs and LSP provide a useful tool to study the physiology of the trigeminal nociceptive system. In ten healthy subjects we recorded the subjective ratings of the perioral laser stimulation and the trigeminal LEPs and LSP before, during and after homotopic experimental tonic muscle (infusion of hypertonic saline into the masseter muscle) and tonic skin pain (topical application of capsaicin to the cheek). LEPs were recorded from the vertex at two stimulus intensities: low (1.1 x pain threshold, PTh) and high (1.5 x PTh). LSP from masseter and temporalis muscles were recorded bilaterally through surface electromyographic (EMG) electrodes. CO(2)-laser pulses were applied to the perioral region (V2/V3) on the painful and non-painful side. The amplitude of LEPs increased with higher stimulus intensities (P<0.0001), but were suppressed by 42.3+/-5.3% during experimental muscle pain (P<0.0001) and by 41.6+/-3.2% during skin pain (P<0.0001). No pain-related effects were observed for the N and P latency of the LEPs (P> 0.20). The LSP in the masseter and temporalis muscles had similar onset-latency (80+/-5 ms), offset-latency (111+/-5 ms) and duration (31+/-4 ms). Experimental pain had no effect on the onset- and offset-latency (P>0.05). Experimental pain, whether from muscle or from skin, reduced the degree of suppression (P<0.01) and the area under the EMG curve (P< 0.005) of the LSP. The LSP was still suppressed during the post-pain recordings when the skin pain had disappeared (P<0.05). In all experiments experimental tonic pain decreased the subjective ratings of the perioral laser stimulation (P< 0.001). Experimental tonic pain, either from muscle or from skin, induced bilateral inhibitory effects on the trigeminal laser evoked potentials and brainstem reflex responses and on the subjective ratings of the laser pulses. These effects could be mediated through the activation of segmental and suprasegmental inhibitory systems that may function interdependently.
Pain 2002 Jul
PMID:Modulation of trigeminal laser evoked potentials and laser silent periods by homotopical experimental pain. 1209 34


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