ISSN:
1432-1106
Keywords:
Cutaneous afferents
;
Primary afferent depolarization
;
Presynaptic inhibition
;
Surround inhibition
;
Spinal cord
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary In five types of mechanoreceptor afferents of the cat's hind foot, the primary afferent depolarization (PAD) induced by mechanical skin stimulation was measured by testing the excitability of their terminations in the dorsal horn. Two types of skin stimuli were used to set up activity in distinct populations of rapidly and slowly adapting mechanoreceptors respectively. The experiments revealed that two systems exist to generate PAD in cutaneous afferents, both being of negative feedback character. One system is activated by impulses from rapidly adapting low threshold receptors and preferentially depolarizes the terminals of such afferents, and correspondingly, the other system is activated by and operates on the slowly adapting units. In both PAD systems the size of the depolarization is graded depending on the stimulus strength. Further, the “tonic” system displays a “surround” pattern of organization similar to that of the “phasic” system which has already been described (Schmidt et al. 1967b). In the discussion the operational relationships of both systems and their functional implications are outlined.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00239166
