THE EFFECTS OF CAPSAICIN, BRADYKININ, PGE2 AND CICAPROST ON THE DISCHARGE OF ARTICULAR SENSORY RECEPTORS INVITRO

The responses of articular sensory receptors to capsaicin, bradykinin, PGE2, and the selective IP-receptor agonist cicaprost were studied in a rat isolated hindlimb in vitro preparation. Long-term maintenance o f normal sensory receptor function was achieved in vitro under conditi ons of combined superfusion and slow perfusion. Response characteristi cs to mechanical or chemical stimuli on articular sensory receptors id entified in this study did not differ to those reported in vivo. This preparation lacks complex effects mediated via spinal or central refle x mechanisms and allows greater control over the physiological environ ment of the receptors being studied. These results support the conclus ion that the effects of capsaicin, bradykinin and the prostanoids are mediated by distinct pharmacological receptors associated with articul ar sensory nerve endings. The potent potentiating effects of cicaprost on bradykinin-induced excitation suggests that these actions are medi ated via IP-receptors.