The contribution of articular receptors to cardiovascular reflexes elicited by passive limb movement.

1. In decerebrate cats, passive movements of one hind limb led to increases in arterial blood pressure, heart rate and ventilation. When both limbs were moved the magnitude of the changes was approximately doubled.2. Section of the nerves to the limb abolished the responses to movement. The responses are, therefore, dependent on a reflex originating in the moving limb.3. The magnitude of the cardiovascular responses was significantly reduced following section of the sensory nerve fibres from the knee joint, in an otherwise partially denervated limb. This indicates that part of the reflex changes associated with limb movement arise from sensory endings in the joints.4. Electrical stimulation of articular nerves led to similar cardiovascular responses. The afferent fibres involved were identified as those having conduction velocities below 18 m/sec, whose terminations are classified as the type IV joint receptors. The possibility that these subserve some other function than pain is discussed.