[Microiontophoretic study of the effect of acetylcholine and noradrenaline on the monosynaptic reflex activity of the spinal cord].

In anesthetized and spinal cats the influence of microionophoretic local injections of acetylcholine and noradrenaline into different layers of grey substance of lumbar segments of the spinal cord were studied with aid of monosynaptic EPSPs of motoneurons. Injections of ACH and NA in the surface layers of the grey substance of dorsal horn induced depression of monosynaptic reactions. In the area of 6--7 layers ACH induced a weak depression, while NA significantly increased the reflex responses. In the given arrangement of motoneurons NA depressed and ACH facilitated extensor and flexor monosynaptic reactions of motoneurons.