Morphological observation of NOS positive CSF-contacting neurons in central nervous system of rat

Objective:To investigate the resources of nitric oxide(NO)of the cerebrospinal fluid(CSF)and its morphology of neuroendocrine,as well as the distribution of nitric oxide synthase(NOS)positive CSF contacting neurons.Methods:The coronal slices of brains and brain stems of 12 Wistar rats were observed using the NADPH d histochemistry method.Results:The NOS positive CSF contacting neurons were mainly at the cerebral aqueduct and the third ventricle(3V).The cell body was located in the central gray substance(especially in the dorsolateral part),dorsal raphe nucleus,dorsolateral tegmental nucleus,and the periventricular nucleus,paraventricular nucleus and the supraoptic nucleus.The NOS positive fibers were extended into the ependyma of the cerebral aqueduct and thd 3V.The NOS containing neurons and the fibers were also seen about the central canal,fundus of fourth ventricle and the surface of the brain.Conclusion:The NO in the CSF comes from the NOS positive CSF contacting neurons surrounding the central canal,third and fourth ventricles,and of the surface of brain.These NOS positive neurons and their fibers synthesize and secrete the NO into the CSF.