Der Schmerz
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Several studies of contingent negative variation (CNV) examined whether this method provides a suitable basis for research on pathogenetic processes in chronic headaches-especially migraine. In the present study, the CNV amplitudes and CNV course of 23 migraine patients were compared with those of 22 healthy subjects. CNV was calculated for (a) "total interval", (b) "early CNV component", and (c) "late CNV component". ⋯ The results allow the assumption that the higher level of CNV amplitude in migraine patients is not only due to higher cortical noradrenergic or serotoninergic activation. This study shows that migraine patients cannot decrease their CNV amplutides. This is probably due to defective processing of sensory imput.
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This paper reviews several recently developed animal models that allow a quantitative assessment of the magnitude of nocifensive behavioral responses across a range of noxious stimulus intensities. Models discussed in detail include: (a) the rodent tail flick reflex, and a modification that allows measurement of tail flick magnitude, (b) rat hindlimb flexion withdrawal reflex elicited by noxious thermal stimulation of the paw, and (c) a learned operant response (nose bar press) evoked by noxious thermal stimulation of the rat's tail. These models are discussed in terms of their advantages over previous methods measuring response threshold, their fulfillment of criteria for ideal pain assessment models, and the neuronal circuitry underlying the behavioral response.
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The quantitative approach to the study of descending inhibition of spinal nociceptive transmission was initiated in Heidelberg through the use of natural, noxious stimulation and examination of the modulation of the encoding properties of spinal dorsal horn neurons. This important approach required control of the noxious stimulus, which had previously been inadequately considered, and the parametric assessment of modulatory influences on the encoding properties of spinal dorsal horn neurons. As a consequence, descending inhibition of spinal nociceptive transmission was found not to be homogeneous throughout the brainstem, but rather to be significantly different from different brainstem nuclei. ⋯ Most recently, the same approach has been profitably applied to studies that have focused onfacilitatory influences descending from many of the same brainstem sites. As a consequence, it has been proposed that there exists an endogenous pain facilitating system analogous to the well-accepted endogenous pain inhibitory system. While the function of the facilitatory system remains unknown, it is proposed that it may be important to long-lasting pain conditions that exist in the absence of pathology.
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This study was designed to evaluate the efficacy of different strategies for migraine prophylaxis over a fairly long period. Metoprolol alone was compared with psychotherapy alone and with a combination of metoprolol and psychotherapy. The psychological programme was planned for future use in preventive treatment. In this paper only the results of the psychological therapy are described. ⋯ According to the results, the efficacy of the psychological treatment increases only gradually, as it has also been demonstrated for biofeedback and relaxation training [9]. Subjectively, patients rate the results of psychotherapy higher than those demonstrated by statistics. This may depend on the selection of patients, but also on the fact that subjective criteria of improvement are not contained in statistical evaluation. Responders and non-responders had initial differences regarding vegetative, hormonal and psychological factors. Responders had a more stable circulatory status, suffered more rarely from menstrual migraine and normally took significantly fewer analgesic drugs. On the whole, this psychological programme has proved quite effective.
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Prolonged administration of morphine for the treatment of chronic pain causes constipation requiring the use of laxatives, which may result in electrolyte deficits. Morphine-induced constipation is due to the binding of the drug to opioid receptors in the gastrointestinal tract and the brain, where it mimics the actions of enkephalins. The effect on the gastrointestinal tract seems to be more intense than the central effect. ⋯ Provided that the anatomical organization of the haemorrhoidal veins in the rat is similar to that in man, slow-release naloxone will be carried by the matrix, to which it is absorbed further down in the gastrointestinal tract. It may thus even reach the rectum, from where, after having been absorbed, it bypasses the liver, enters the central nervous system and reduces the antinociceptive effect of morphine. In conclusion, it can be stated that oral administration of naloxone in combination with morphine may help to prevent constipation during the treatment of chronic pain.