Study of the early somatosympathetic reflex response.

Using anesthetized cats, we studied the early components of the somatosympathetic reflex in the white rami communicantes of segments T(3) and L(2) in response to stimulation of the corresponding segmental somatic nerves. The results show that the early somatosympathetic reflex is a complex and highly organized response consisting of three typical waves. The shortest latency wave of this reflex was investigated in detail and evidence of its monosynaptic nature was obtained. Calculations showed that the efferent part of this reflex component may be formed by sympathetic preganglionic neurons with axonal conduction velocities of about 10 m/sec or more.