Theexcitatory effect induced by caerulein (5-20ng/kg, i. v.) on the movements of the denervated jejunal loop is more powerful than that on the innervated one. Using dogs anesthetized with pentobarbital sodium (25mg/kg, i. v.), the mechanism of this phenomenon was studied.
1. On the innervated jejunum, the excitatory effect of caerulein was markedly increased after bilateral splanchnicotomy, the transection of spinal cord at the level of 5th cervical segment or decerebration between superior and inferior colliculi, whereas the effect was unchanged after bilateral vagotomy at the neck.
2. From the results obtained, it was concluded that caerulein probably induced the excitation of sympathetic area in the brain cranial to the superior colliculus, which caused spinal sympathetic activation, resulting in inhibition of the intestinal motility through the splanchnic nerves, while caerulein caused the excitatory effect on the intestinal motility through the excitatory myenteric neurones, as reported in the Previous paper.
