MEASUREMENT OF VASOACTIVITY IN THE GUINEA-PIG CHOROID

Purpose: A perfusion system for studying the vasoactive properties of the guinea-pig choroid is described. Methods: The principle of operati on is that the vascular resistance of the entire Vascular network oi a n isolated, perfused eye can be monitored by recording the pressure re quired to deliver a constant flow of perfusate through the network Del ivery of the pharmacological agent of interest into the perfusate stre am and the subsequent determination of the magnitude of any induced pr essure changes allows the vasoactive potency oi various agonists to be assessed. Results: The baseline vascular resistance was 1.35 +/- 0.16 mmHg.min/mu L (mean +/- SEM; n = 10) and the mean response to intralu minal delivery of 124 mmol/L K+ Krebs was an increase in resistance of 297 +/- 67%. Vasoactive responses were sustainable for more than 8 h. Conclusions: This system will now be used to study the vasoactive pro perties of the guinea-pig choroid in greater detail.