Essay about Actions of Drugs

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Pages: 9

Actions of drugs on cardiovascular preparations

The experiment outlined in this report was carried out with the intention to observe and explore the effects of certain named drugs on a vascular preparation, in the cardiac region specifically. The cardiovascular preparation used in this experiment was an isolation of the descending aorta of a rat. This isolate is particularly useful as it mirrors the responses that would be observed in a human sample, thus this experiment will give rise to conclusions applicable to humans. The drugs which will be tested are as follows: acetylcholine, adrenaline, 5-hydroxytryptamine, isoprenaline, noradrenaline and sodium nitroprusside. As the preparation, inherently was not in a live
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The sample was then left for another three minutes to re-equilibrate before the next drug was tested. If a significant change was not seen after the first two minutes then the dosage was doubled and injected in addition to the initial installment. Whilst performing this experiment it was carried out with the understanding that the affects of a vasodilator would not necessarily be seen unless it was being exposed to the tissue in a pre-constricted state. Accordingly, measures were taken such that vasodilators would be applied directly after a vasoconstrictor, with the rinsing steps omitted so that their true affects could be observed. The named drugs were applied in the following concentrations:

Table 1. Final bath concentrations used for each drug.

Drug | Final Bath
Concentration | Noradrenaline | 1×10-7 mol/l | Isoprenaline | 1×10-7 mol/l | Adrenaline | 1×10-7 mol/l | Phenylephrine | 1×10-7 mol/l | Acetylcholine | 1×10-6 mol/l | Sodium Nitroprusside | 1×10-8 mol/l | 5-Hydroxytryptamine | 1×10-5 mol/l |

With regard to the second part of the experiment, serial dilutions were produced with a range of concentrations reaching from order 10-9 M to 10-5 M solutions with intermediary steps also included. Experimental procedure mirrored the techniques outlined earlier, rinsing the tissue in between each trial.


Table 2. The results as determined from the graphs drawn by