SOMATIC AND AUTONOMIC REFLEXES IN SPINAL MONKEYS

Abstract

In Macaca mulatta monkeys, simultaneous skin and rectal temps. were measured by the Leeds-Northrup (micromax) recorder. Immersion of one lower extremity in ice-water for 20 mins. produced an avg. fall of 4-5[degree]F. in the web between the hallux and first toe of the non-immersed opposite extremity. The fall in temp. was less marked when the immersed extremity was constricted by a tourniquet. Transections of the cord under aseptic precautions in 9 monkeys from 6C to 12D levels produced the well-known condition of spinal "shock," with abolition of all somatic reflexes, paralysis of bowel and bladder function, dryness of the skin, absence of piloerection, and vasomotor paralysis, the latter condition being evidenced by skin temps. of the feet which paralleled and approximated the rectal temp. During this period of "shock" cooling one lower extremity did not cool the opposite limb. Return of somatic reflexes preceded the reestablishrnent of autonomic functions, which were usually functioning by the end of the 2d wk. after operation, but were less efficient than those of the normal animal. The crossed cooling response, appearing after several wks., was less pronounced after the operation. Partial lesions of the cord merely depressed the crossed cooling response. Lumbar (pre-ganglionic) sympathectomy temporarily eliminated the crossed cooling response, which was mediated both by the nervous system and the vascular system.