Effects of prostaglandins E1, E2, A1, A2, and F2α on canine carotid arterial blood flow, cerebrospinal fluid pressure, and intraocular pressure

Abstract

✓ The effects of intra-arterial (i.a.) or intravenous (i.v.) injection of prostaglandins E1, (PGE1), E2 (PGE2), A1 (PGA1), A2 (PGA2), and F2α (PGF2α) on the carotid circulation, intraocular pressure (IOP), and cerebrospinal fluid pressure (CSFP) in anesthetized dogs are reported. Direct i.a. injection of PGE1, PGE2, or PGA2 decreases the carotid vascular resistance whereas PGF2α increases it. The i.v. injection of PGE1, PGE2, and PGA2 increases heart rate, carotid arterial blood flow, IOP, and CSFP as systemic arterial pressure decreases, while the i.v. injection of PGF2α decreases all but the IOP. Both systemic arterial pressure and IOP increase during a single i.v. infusion and decrease during a continuous i.v. infusion of PGF2α. This suggests that the changes in IOP and CSFP by the prostaglandins are not only a direct effect but also reflect indirect influence on carotid arterial blood flow. During a continuous i.v. infusion of PGE1, PGE2, or PGA2, carotid arterial blood flow gradually decreases toward control values after its initial marked increase. It is concluded that a single i.a. or i.v. injection or a short i.v. (10 min) infusion of PGE1 or PGE2 may be more effective than a prolonged continuous i.v. infusion of PGE1 or PGE2 for alleviating cerebral vascular spasm.