Cerebrospinal fluid levels of cyclic nucleotides in non-neoplastic hydrocephalus: preliminary report.

Cerebrospinal fluid levels of cyclic nucleotides in children with hypertensive communicating hydrocephalus secondary to leptomeningitis were investigated. 3':5'-cAMP and 3':5'-cGMP values were uniformly increased in pre-operative findings, suggesting a "passive" behaviour of the blood brain barrier after the inflammatory lesion. After ventriculo-peritoneal shunt, the mean ratio between the two nucleotides gradually became negative, with a marked increase of cGMP levels, probably related to selective barrier damage. In patients with shunt obstruction, the altered cAMP/cGMP ratio showed a gradual regression towards normal, due to a decrease in the cGMP level. The important role of endocranial pressure changes in the "second messenger" turnover is stressed.