In vivo and in vitro effects of magnesium sulfate in the cerebrovascular bed of the goat.
The effects of magnesium sulfate in the cerebrovascular bed were studied both in vivo, by measuring cerebral blood flow in conscious nonpregnant goats, and in vitro, by recording isometric tension in isolated goat middle cerebral arteries. Injections of increasing doses (10 to 300 mg) of magnesium sulfate directly into the cerebral circulation elicited transient and dose-dependent increases in cerebral blood flow and decreases in cerebral vascular resistance. Similar results were obtained when increasing doses (0.3 to 3 gm/15 min) of magnesium sulfate were infused intravenously, although the vasodilatations reached a stable plateau that remained when the infusions finished. Cumulative addition of magnesium sulfate (10(-5) to 3 x 10(-2) mol/L) did not change the isometric tension of isolated arterial segments at resting tone, but relaxed in a concentration-dependent manner the arterial segments preconstricted with 10(-5) mol/L prostaglandin F2 alpha. These results demonstrate that magnesium sulfate acts as a dilator in the cerebral circulation by acting directly on the cerebral arteries. This could explain, at least in part, its beneficial effects on preeclampsia-eclampsia.
Perales
A J
AJ
Hospital Maternal, Universidad de Valencia, Spain.
Torregrosa
G
G
Salom
J B
JB
Miranda
F J
FJ
Alabadí
J A
JA
Monleón
J
J
Alborch
E
E
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002536:Cerebral Arteries / Q000187:drug effects; D002560:Cerebrovascular Circulation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006041:Goats; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D007262:Infusions, Intravenous; D007269:Injections, Intra-Arterial; D007537:Isometric Contraction / Q000187:drug effects; D008278:Magnesium Sulfate / Q000494:pharmacology*; D013997:Time Factors; D014655:Vascular Resistance / Q000187:drug effects
D008278:Magnesium Sulfate