Pain
-
In 40 rats anaesthetized with enflurane, we identified convergent dorsal horn neurones responding to both noxious (pinch) and innocuous (brush) mechanical stimulation of their receptive fields on the tail. We recorded extracellular activity before and during ischaemia of the receptive fields, as well as during subsequent reperfusion. Two NSAIDs, indomethacin and diclofenac sodium, or saline were applied locally to the spinal cord before the induction of ischaemia. ⋯ The neurones became hypersensitive to both pinch and brush during reperfusion of their receptive field, and receptive field size increased. Application of indomethacin and diclofenac sodium to the spinal cord abolished both the hypersensitivity and the increase in receptive field size. Our results indicate that spinal cord prostanoid synthesis facilitates the enhanced excitability of dorsal horn convergent neurones to both noxious and innocuous mechanical stimuli during reperfusion of their receptive fields, but does not affect the neurones' responses to receptive field ischaemia, nor their responses to mechanical stimuli in the absence of a conditioning stimulus.
-
The involvement of the basal ganglia in motor functions has been well studied. Recent neurophysiological, clinical and behavioral experiments indicate that the basal ganglia also process non-noxious and noxious somatosensory information. However, the functional significance of somatosensory information processing within the basal ganglia is not well understood. ⋯ Frequently, these patients have intermittent pain that is difficult to localize. Collectively, these data suggest that the basal ganglia may be involved in the (1) sensory-discriminative dimension of pain, (2) affective dimension of pain, (3) cognitive dimension of pain, (4) modulation of nociceptive information and (5) sensory gating of nociceptive information to higher motor areas. Further experiments that correlate neuronal discharge activity with stimulus intensity and escape behavior in operantly conditioned animals are necessary to fully understand how the basal ganglia are involved in nociceptive sensorimotor integration.
-
The formalin test is increasingly used as a model of injury-produced pain but there is no generally accepted method of pain rating. To examine the properties of various pain rating methods we established dose-response relations for formalin injected in the plantar surface of one hind paw, and the analgesic effects of morphine and amphetamine using the most frequently reported behavioural measures of pain (favouring, lifting, licking and flinching/shaking of the injured paw) and combinations of these. Licking, elevation and favouring of the injected paw showed a biphasic response at all formalin doses. ⋯ The interphase depression of pain, as well as the analgesic effects of morphine and amphetamine, were all associated with increased motor activation. Power analysis indicated that using a moderate dose of formalin and a combined pain score gave the greatest power to detect differences in pain. It was also found that pain scores increase with ambient temperature and that rat strains may differ in formalin pain sensitivity.
-
Disability accompanying occupational low back pain (LBP) can include a wide range of incapacitating symptoms which, for the practitioner, can be time-consuming and difficult to identify systematically. A questionnaire designed for case-finding and assessment could assist in both the early recognition of disability and in planning management. A suitable questionnaire for clinical use could not be found in the literature. ⋯ The questionnaire includes 79 items based on the subjects' perceived health status. The response structure of the CBSQ has been adapted from that of the General Health Questionnaire (GHQ) and some items in the CBSQ have been developed from items in the Sickness Impact Profile (SIP) and GHQ. The questionnaire discriminates effectively between subjects with different degrees of disability, it correlates quite well with the SIP, test-retest reliability for the whole questionnaire is 0.98, the receiver-operating characteristics are more favourable than those for the SIP, and the CBSQ screening score provides an index of severity which correlates with work incapacity.(ABSTRACT TRUNCATED AT 250 WORDS)