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Biomedical subjects

R G Hallin

Publications and source records attributed to R G Hallin.

50 records · Page 3Linked to original sources
PubMed1974

Responses in human A and C fibres to repeated electrical intradermal stimulation.

The responses of A and C fibres to electrical intradermal stimulation were recorded with microelectrodes inserted percutaneously into intact human skin nerves. Unitary discharges deriving from A fibres were often encountered and sometimes even single C unit deflections were identified. When several C fibres responded to the stimulation, a compact time presentation of the filtered and dot-converted spikes improved the discrimination of individual spikes time-locked to the stimulation, so that unitary C elements could often be identified in the treated records even if the signal-to-noise ratio of the original signals was low. Increases in latency or blockings were traced in both A and C unit responses to repeated excitation, but the influence of repeated activation was more pronounced in thin nerve fibres even at low stimulation frequencies. The decreased excitability of thin nerve endings on repetitive stimulation suggests that not only central factors but also excitation failure in peripheral thin nerve fibres might be responsible for the decrease in pain perception experienced during local intense electrical intradermal stimulation at high frequencies.

Adult↗
PubMedDate not supplied

Possible role of sympathetic activity in abnormal behavior of rats induced by lesion of the sciatic nerve.

The role of genetic differences and environmental stress in the form of continuous exposure to cold in the production of abnormal behavior in rats was examined by subjecting the animals to unilateral sciatic nerve section. Some nerve-lesioned Sprague-Dawley (SD) rats responded to the cold by developing a state we termed stress-related pain behavior (SRPB). These animals also self-mutilated the denervated limb (autotomized) more often than cold-exposed rats that did not develop SRPB. The role of genetic differences was studied by also subjecting Wistar-Kyoto (WK) and spontaneously hypertensive (SHR) rats to sciatic nerve section and cold. Both WK and SHR rats, which have a higher level of circulating catecholamines than SD rats, autotomized significantly less than SDs, and did not exhibit SRPB. The results suggest that differences in susceptibility to stress and genetic variability may be important factors in the development of abnormal and/or pain behaviors following peripheral nerve trauma.

Animals↗
PubMedDate not supplied

Does sympathetic activity modify afferent inflow at the receptor level in man?

Results from animal experiments have indicated that the normal sensory input into the central nervous system can be modulated by sympathetic nervous outflow at the receptor level. Preliminary data obtained with a new type of percutaneous electrode suggest that there may be a linkage between ongoing activity in Pacinian corpuscle (PC) afferents and skin sympathetic activity in conscious humans. Further studies attempting to evaluate the possible linkage between afferent and sympathetic nerve functions in man may be of substantial physiological and clinical interest.

Afferent Pathways↗