STUDIES ON SOME ENDOGENOUS DINUCLEOSIDE POLYPHOSPHATES AND THEIR EFFECTS ON THE CARDIOVASCULAR SYSTEM

Abstract

In the present work two different sets of experiments were carried out. The first set was in-vitro using the isolated perfused rat kidney and the second one was in-vivo investigations of haemodynamics in anaesthetised rats.

In the in-vitro experiments the left kidney was isolated from anaesthetised rats and perfused with Tyrode's solution under constant flow conditions, where the pressure is proportional to the vascular resistance. The perfusion pressure was monitored in response to different doses (0. 5- 100 tM) of each of the studied diadenosine polyphosphates; AP2A- APsA. The same doses were repeated again after perfusion of each of the following purinoceptor antagonists:

purinoceptor antagonists: (a) Suramin; non selective P2 antagonist, (b) a,j3-MeATP; P2x desensitiser and (c) PPADS; selective P2x antagonist.

2. P1 purinoceptor antagonists including: (a) CPDPX; A1 antagonist and (b) DMPX; A2 antagonist

The in-vivo experiments were carried out on anaesthetised rats, prepared for measurement of several haemodynamic parameters. The Mean Arterial Blood Pressure and Heart Rate were measured using an intracarotid polyethylene catheter connected, via a pressure transducer, to a small animal flowmeter and a computer-aided biological monitoring