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

✓ The effects of intra-arterial (i.a.) or intravenous (i.v.) injection of prostaglandins E 1 , (PGE 1 ), E 2 (PGE 2 ), A 1 (PGA 1 ), A 2 (PGA 2 ), and F 2α (PGF 2α ) on the carotid circulation, intraocular pressure (IOP), and cerebrospinal fluid pressure (CSFP) in anesthetized dogs are reported. Direct i.a. injection of PGE 1 , PGE 2 , or PGA 2 decreases the carotid vascular resistance whereas PGF 2α increases it. The i.v. injection of PGE 1 , PGE 2 , and PGA 2 increases heart rate, carotid arterial blood flow, IOP, and CSFP as systemic arterial pressure decreases, while the i.v. injection of PGF 2α 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 PGF 2α . 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 PGE 1 , PGE 2 , or PGA 2 , 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 PGE 1 or PGE 2 may be more effective than a prolonged continuous i.v. infusion of PGE 1 or PGE 2 for alleviating cerebral vascular spasm.