[Properties of the mechanoreceptors of the nipple of the guinea pig mammary gland. (Rapidly adapting mechanoreceptor units)].
Two types of rapidly adapting mechanosensitive units have been found in skin of the teat of guinea--pig mammary gland (RA1 and RA2). They wee not both spontaneously active. RA1 and RA2 have no position response. The relation between average frequency of discharge and displacement velocity at a constant displacement amplitude was linear for RA1. With constant velocity displacements, frequency versus displacement curves assume a horizontal orientation of relatively low discharge frequencies and are then displaced upward as velocity increases for RA1. The number and frequency of afferent impulses of RA1 decreased during repeated ramp mechanical stimulation. Vibratory tuning points were in the range of 10--25 Hz for RA1. 20% of mechanosensitive units were RA2, which have a high velocity threshold and rarely produce more than 2--3 impulses to high velocity. The fatigue of RA2 is not prominent. RA1 were classed as the velocity detectors and RA2 as "transient" detectors.
D000200:Action Potentials; D000222:Adaptation, Physiological; D000818:Animals; D001940:Breast / Q000294:innervation*; D005260:Female; D006168:Guinea Pigs; D008465:Mechanoreceptors / Q000502:physiology*; D009558:Nipples / Q000294:innervation*
Svoistva mekhanoretseptorov soska molochnoĭ zhelezy morskoĭ svinki. (Bystroadaptiruiushchiesia mekhanoretseptornye edinitsy)