ISSN:
1432-1106
Keywords:
Mechanoreceptors
;
Cutaneous Afferents
;
Afterpotentials
;
Primary Afferent Depolarization
;
Spinal Cord
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Mechanoreceptors of the hairy skin and the central pad of the cat's hind foot were activated using piezo-electric crystals as mechanical stimulators. Their afferent fibres were traced in the lumbar spinal cord by stimulating antidromically and by recording the collision of the antidromic and orthodromic action potentials. Low threshold mechanoreceptor units could be stimulated in isolation. It was possible, therefore, to follow the postspike excitability changes of their fibres in the spinal cord without interference from other spinal cord potentials. Primary afferent depolarization has been induced in cutaneous afferents by stimulating muscle and cutaneous nerves. It has been found that the a cutaneous fibres of mechanoreceptors were depolarized by volleys in a cutaneous fibres and to a lesser degree by volleys in Group I b, II and III muscle afferents but not by high threshold cutaneous afferents. The primary afferent depolarization of cutaneous fibres has been subjected to the action of an impulse propagating down that fibre to its central terminals. Excitability testing revealed that the amplitude and the time course of the primary afferent depolarization were only altered up to about 30 ms after the impulse indicating an active depolarization of the presynaptic terminals.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00235586
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