Octreotide, a somatostatin analogue, attenuates movement evoked discharges of fine afferent units from inflamed knee joints of rats

Abstract

This electrophysiological study examined whether octreotide, a stable analogue of somatostatin (SOM), reduces the mechanosensitivity of fine primary afferents from inflamed knee joints of rats similarly to SOM itself (Pain 73 (1997) 377). Close intra-arterial application of 200 μl of octreotide (10 −6–10 −3 M) dose-dependently diminished the responses to passive non-noxious and noxious rotations of the joint in most of the units tested. The inhibitory effects of octreotide required a higher concentration (10 −3 M) compared to SOM to successfully decrease the number of recorded spikes. Application of cyclo-somatostatin, a SOM antagonist, before the octreotide injection prevented the reduction of the movement evoked discharges. These data indicate that octreotide is able to successfully decrease the responses of mechanosensitive fine afferent units innervating the inflamed knee joint of the rat and may, therefore, be useful in the treatment of articular pain of peripheral origin.