Cardiovascular and Somatic Reflexes in Experimental Allergic Encephalomyelitis

Abstract

Experimental allergic encephalomyelitis (EAE) in rats is characterized by flaccid hindlimb paralysis, urinary incontinence and fecal impaction. Somatic and cardiovascular reflexes were studied in these animals. At varying degrees of stretch of the gastrocnemius-soleus-plantaris group of muscles or of the anterior tibial muscle, stimulation of the sciatic nerve increased the isometric tension of these muscles similarly in normal and paralyzed rats. Reflex contraction of the anterior tibial muscle was produced in normal rats by posterior tibial nerve stimulation. This response was completely blocked in paralyzed rats. Stimulation of the central end of the ligated sciatic nerve at various parameters reduced blood pressure. The magnitude of this effect was less in the paralyzed group. Although vasoconstriction in the perfused hindquarters resulting from bilateral stimulation of the cervical vagus was also reduced in paralyzed rats, the response to lumbar sympathetic chain stimulation was the same in both groups. Thus, in EAE the peripheral nerve-muscle elements in blood vessels and the skeletal muscle responded normally but effects requiring the participation of the central nervous system were depressed.