Influence of arachidonic acid on vasoconstrictor responses in the rabbit hindquarters vascular bed.

The effects of infusion of arachidonic acid (AA) on responses to pressor hormones and sympathetic nerve stimulation were investigated in the hindquarters vascular bed of the rabbit. During infusion of AA, vasoconstrictor responses to norepinephrine, nerve stimulation and angiotensin II were reduced to a similar extent. In addition, AA decreased hindquarters perfusion pressure and systemic arterial pressure. Following the administration of indomethacin, vasoconstrictor responses as well as perfusion pressure and aortic pressure remained unchanged during infusion of AA. The present data show that AA possesses the ability to modulate responses to nerve stimulation and pressor hormones. In addition, AA dilates the hindquarters vascular bed and produces a systemic depressor response. The present data suggest that cyclooxygenase products possessing vasodilator activity may mediate the effects of AA on the sympathetic nervous system and responses to pressor hormones in the rabbit hindquarters vascular bed.