Production of cyclic nucleotides from normal human brain.

Concentrations of cyclic AMP and cyclic GMP in arterial and internal jugular venous (IJV) blood were determined at the resting wakeful state in thirty surgical patients without neurological deficits. The levels of cyclic AMP in artery and IJV were 32.1 +/- 3.0 and 40.0 +/- 4.1 pmol/ml (means +/- standard errors), respectively, while those of cyclic GMP in artery and IJV were 12.2 +/- 2.7 and 14.4 +/- 3.0 pmol/ml, respectively. Concentrations of both cyclic nucleotides in IJV were significantly higher (P less than 0.001) than those in artery. IJV-arterial differences for cAMP and cGMP were 7.9 +/- 1.7 and 2.1 +/- 0.5 pmol/ml, respectively. The results indicate that both cyclic nucleotides are constantly produced and released from the normal human brain.