Lamina-specific Suppression and Acceleration of Dorsal-horn Unit Activity by Nitrous Oxide: A Statistical Analysis

Abstract

The effect of 75 per cent nitrous oxide–oxygen upon the spontaneous unit activity of cells in Rexed laminae IV, V, and VI of the dorsal horn of spinal cats was analyzed quantitatively with the aid of several digital computer programs. Overall statistical parameters, interval histograms, and burst-interval histograms were derived. Each cell lamina was characterized by a “statistical signature.” The spontaneous activity of lamina IV cells remained unaffected by the gas. The spontaneous activity of lamina V cells showed an increase in mean interval, accounted for by an increase in interburst interval, with relative maintenance of intraburst interval duration. The spontaneous activity of lamina VI cells was increased in rate and regularized in pattern. The cellular effects of analgesic agents cannot be described by overall statistical parameters alone, but require specification of the interval “fine structure” of spontaneous unit activity.