Computer analysis of intraarterially recorded blood pressure in conscious unrestrained rats.

A precise knowledge of cardiovascular activity and its pharmacological modifications in the conscious unrestrained animal requires intraarterial blood pressure recording for long periods of time. For that purpose, a technique was developed involving chronic catheterization of the rat abdominal aorta and the use of a computer system to perform the digitization of the blood pressure signal and the on-line calculation of five cardiovascular parameters. By means of duplexing, two rats (one treated and one control) can be studied simultaneously. Off-line processing is devoted to the graphic treatment and statistical analysis of the data. The effects of a single intravenous administration of dihydralazine are presented in order to show the usefulness of the technique.