The effect of acute joint distension on mechanoreceptor discharge in the knee of the cat.
Recordings were obtained from afferents travelling in the posterior articular nerve of the cat knee joint. These arose from tonically active slowly adapting mechanoreceptors which were located in the joint capsule and whose conduction velocities were in the group II range. Intraarticular fluid injection resulted in enhancement of receptor discharge. Both the static index (adapted discharge 2 s after ramp displacement) and the dynamic index (difference between peak discharge during joint displacement and that occurring 0.5 s later) increased after injection. However, whereas the dynamic index increased by three- to fivefold the static index never exceeded a twofold increase. Incremental rise of intra-articular volume resulted in progressive increase in both parameters at all angular velocities. Thus both position and velocity sensitivity are enhanced by the acute introduction of fluid into the synovial cavity.
D000818:Animals; D002415:Cats; D003911:Dextrans / Q000008:administration & dosage; D007270:Injections, Intra-Articular; D007719:Knee Joint / Q000294:innervation / Q000502:physiology*; D008465:Mechanoreceptors / Q000502:physiology*; D009068:Movement; D009431:Neural Conduction; D009475:Neurons, Afferent / Q000502:physiology*
D003911:Dextrans