Effect of Saline

In the experiments which follow pharmacological agents are dissolved in a small volume of saline and administered intravenously. The injection of this small volume of fluid into a rat, with a relatively small blood volume of about 20 ml, produces small transitory changes in both blood pressure and heart rate. These are artefacts of the injection volume and are not pharmacological effects. You should be aware of these artefacts when interpreting the results of experiments.

This section presents the results of injecting three different volumes of saline (0.2, 0.4 and 0.6 ml/kg). You should study these responses before proceeding to the other experiments.