Differences in the central actions of arachidonic acid and prostaglandin F2 alpha between spontaneously hypertensive and normotensive rats.
Prostaglandin F2 alpha (PGF2 alpha) is one of the most common metabolites of arachidonic acid (AA) in rat brain. When administered intracerebroventricularly (i.c.v.) to rats, both AA and PGF2 alpha exert dose-related hypertensive, tachycardic and hyperthermic effects. Metabolic alterations in the endogenous formation of some prostaglandins in the brain-stem of spontaneously hypertensive rats (SHR) have been reported. Therefore the central effects of AA and PGF2 alpha on blood pressure, heart rate and body temperature were studied by in SHR and normotensive Wistar rats (NR) under urethane-anaesthesia. The hypertensive effect of AA i.c.v. (0.01-100 micrograms/rat) was larger in magnitude of SHR than in NR, but there was no significant difference in the AA-induced changes of heart rate and body temperature between the groups. Pretreatment of NR with sodium meclofenamate (1 mg/rat i.c.v.) antagonised the central effects of AA indicating that these effects are not due to AA itself but it its conversion to prostaglandins. Unlike the effects of AA, the central hypertensive, tachycardic and hyperthermic responses to PGF2 alpha (0.5-50 micrograms/rat i.c.v.) were significantly attenuated in SHR. The present results obtained with AA are compatible with the previous assumption that the synthesis of prostaglandins in the brain of SHR might differ from that in NR. The results also demonstrate that the central effect of PGF2 alpha are reduced in SHR.
D000818:Animals; D001095:Arachidonic Acids / Q000008:administration & dosage / Q000378:metabolism / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects; D015237:Dinoprost; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008469:Meclofenamic Acid / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology*; D051381:Rats
D001095:Arachidonic Acids; D011460:Prostaglandins F; D008469:Meclofenamic Acid; D015237:Dinoprost