[Alteration of atrial natriuretic peptide and cyclic GMP in cerebrospinal fluid in canine kaolin-induced hydrocephalus].

CSF and Plasma concentrations of atrial natriuretic peptide (ANP) and cyclic GMP (cGMP), which is regarded as a second messenger of ANP, were measured intermittently during the progress of canine kaolin-induced hydrocephalus. Data were analyzed being divided into three groups, normal, acute (within 2 weeks after intracisternal injection of kaolin suspension) and chronic (from 3 to 4 weeks after injection of kaolin suspension) stages of hydrocephalus. The presence of ventricular dilatation was evaluated by MRI or postmortal dissection. ANP, cGMP in CSF and CSF pressure significantly increased in the acute stage of hydrocephalus. In the chronic stage, ANP in CSF and CSF pressure had no statistical difference with data of the normal stage. Cyclic GMP in CSF kept significantly high value in the chronic stage of hydrocephalus. CSF concentrations of Na, CSF osmolarity, plasma ANP, plasma cGMP, plasma ADH, serum Na and serum osmolarity did not change significantly in the course of hydrocephalus. There was a significant positive correlation between ANP in CSF and CSF pressure. ANP in CSF did not correlate with degree of ventricular dilatation. Cyclic GMP in CSF did not correlate with ANP in CSF, nor with CSF pressure. These data suggest that concentration of ANP in CSF may alter directly or indirectly depending on CSF pressure in kaolin-induced hydrocephalus. And cGMP in CSF was suggested to depend not on ANP in CSF, but on other unknown factors in kaolin-induced hydrocephalus.