[NADPH-DIAPHORASE REACTIVITY IN THE VENTRAL HORN OF THE FELINE SPINAL CORD DURING ACUTE MUSCLE INFLAMMATION]

The aim of this research was to reveal the changes in the NADPH-d reactivity in the lumbal spinal cord (L6/L7) of cats with unilateral acute myositis of the mm. gastrocnemius-soleus after intramuscular injections of carrageenan. The effect of unilateral muscle inflammation was expressed in a significant increase in the number of NADPH-d-reactive neurons in ipsilateral and contralateral intermediate (lamina VII; 17.62 ± 2.7 and 20.67 ± 13.3) and medial (lamina VIII; 7.3 ± 1.9 and 6.0 ± 2.1 respectively) zones of the ventral horns. However, a clear decline of the reactive cells was recorded on the ipsilateral side within the area around the central canal (lamina X). An increase in the NADPH-d reactivity within the ventral horns on both sides on the spinal cord and the induction of such reactivity (contralaterally) in large multipolar neurons localized in the dorsal part of the intermediate zone were revealed in cats with unilateral acute muscle inflammation. It is hypothesized, that during acute myositis, plastic changes in different layers of the dorsal and ventral horns activate the processes of disinhibition due to an increase in the number of NOS-containing/NADPH-d-reactive neurons in the spinal gray matter.