title: Cyclic nucleotides and cerebrovascular tone in newborn pigs.
abstract: Relationships between cyclic nucleotides and cerebrovascular tone were investigated using closed cranial windows in anesthetized newborn pigs. Pial arteriolar diameter was monitored and cerebrospinal fluid (CSF) was collected from beneath the cranial window. Adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) concentrations in CSF were 1,690 +/- 200 and 730 +/- 40 fmol/ml, respectively. Topically applied isozyme-selective and nonselective inhibitors [3-isobutyl-1-methylxanthine (IBMX), theophylline, Ro 201724, dipyridamole, zaprinast, calmidazolium, and W-7] of cyclic nucleotide phosphodiesterases dilated pial arterioles with concomitant increases in cAMP and/or cGMP levels in CSF. Topical application of dibutyryl-cAMP and dibutyryl-cGMP also resulted in pial arteriolar dilation. Ten-minute hypercapnia, which results in pial arteriolar dilation, increased cAMP to 5,240 +/- 900 and cGMP to 1,350 +/- 200 fmol/ml. IBMX and zaprinast potentiated the increases in cAMP and cGMP as well as the cerebrovascular dilation in response to hypercapnia. These data suggest that cyclic nucleotides contribute to regulation of cerebral vascular tone during control conditions. Furthermore, cAMP and/or cGMP appears to be involved in arterial vasodilation in response to hypercapnia in newborn pigs.
authors.affiliation: Department of Physiology/Biophysics, University of Tennessee, Memphis 38163.
authors.forename: H
authors.initials: H
authors.lastname: Parfenova
authors.forename: M
authors.initials: M
authors.lastname: Shibata
authors.forename: S
authors.initials: S
authors.lastname: Zuckerman
authors.forename: R
authors.initials: R
authors.lastname: Mirro
authors.forename: C W
authors.initials: CW
authors.lastname: Leffler
mesh_terms: D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000134:cerebrospinal fluid; D000818:Animals; D000831:Animals, Newborn; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D000242:Cyclic AMP / Q000134:cerebrospinal fluid / Q000494:pharmacology*; D006152:Cyclic GMP / Q000134:cerebrospinal fluid / Q000494:pharmacology*; D006935:Hypercapnia / Q000134:cerebrospinal fluid; D007093:Imidazoles / Q000494:pharmacology; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D013449:Sulfonamides / Q000494:pharmacology; D013552:Swine; D014666:Vasomotor System / Q000187:drug effects*
chemical_list: D007093:Imidazoles; D010726:Phosphodiesterase Inhibitors; D013449:Sulfonamides; C031938:calmidazolium; C017967:W 7; D000242:Cyclic AMP; D015105:3',5'-Cyclic-AMP Phosphodiesterases; D006152:Cyclic GMP