Biomedical subjects

N Mei

Publications and source records attributed to N Mei.

92 records · Page 6Linked to original sources

PubMedDate not supplied

[Cutaneous and muscular unmyelinated afferent fibres. Clinical, histological and experimental study. Possible explanation of muscular cramps (author's transl)].

Unmyelinated afferent fibres are the most numerous of the whole afferent component. Their function in nociception is now well established. However some recent data allow to think that their function is much more complex. Cutaneous unmyelinated afferences are evaluated in controls and in 3 groups of patients (painful neuropathies, painless neuropathies with hypesthesia, diabetic neuropathies). Amyelinic myelinic ratio is not in accordance with the gate control theory. Muscular afferent fibres are studied, especially the lateral gastrocnemius soleus nerve of cat. Their predominance is obvious. Our study was conducted by recording single unit activity from a micro electrod inserted in dorsal root ganglia. But 45% of unmyelinated fibres are not activated by various algesic stimuli. It is suggested that they have a function in cardio-pulmonary adaptation to effort and possibly segmental vascular control as homonymous reflex effect on moto-neuron. Their several properties are a possible explanation of muscular cramps.

Adult↗

PubMedDate not supplied

Electrophysiologic evidence showing the existence of sensory receptors within the alveolar bone in anesthetized cats.

Single-nerve activities were recorded in the gasserian ganglia of anesthetized cats by glass extracellular micro-electrodes to determine whether sensory endings exist within the alveolar bone. Trigeminal cells responded to mechanical and/or thermal stimulation applied to the maxillary bone. Some were activated by specific kinds of fairly precise mechanical stimuli (moderate forces applied in a preferential direction); others exhibited a coarse mechanical sensitivity. In addition, electrical stimulation was applied to the maxillary bone to determine the conduction velocities of the relevant fibers. These mainly ranged between 1 and 6 m/s, which indicates that the fibers belonged to the small-diameter category (thinnest myelinated and unmyelinated fibers). Similar results were obtained from animals with osseointegrated implants. It was concluded that the alveolar bone is endowed with sensory endings capable of detecting mechanical and thermal changes, and that these receptors may provide compensatory sensitivity in edentulous subjects whose main (periodontal) sensitivity has been eliminated.

Action Potentials↗