Drugs X Allergies

PRACTICAL REPORT – DRUGS AND ALLERGIES

16/04/2015

Andressa Florenzano Maeda

Practical partners: Katharina de Barros Correia, Ralph and Ashley.

Demonstrator group:

METHODS

To this practical an isolated guinea-pig ileum was used in an organ bath setup. It was bathed in Holman’s solution at 34oC, gassed with carbogen and under a resting tension of 1g by the Grass FT03 isometric force transducer. All the data were recorded by PowerLab recording system.

         This practical was separated in two parts: Preparation 1 and 2.

For the first part, ”Preparation 1”, the tissue was prepared and the experiments were made based on page 24 of the Practical Guide 2015. My branch was responsible for experiment with the “control tissue”. And for the second part, ”Preparation 2”, my partner and I used the “Indomethacin treatment” following the steps in page number 25 of the Practical Guide 2015 as well.

RESULTS

In preparation 1 we got 2 different results: Part 1 and part 2.

Preparation 1 part 1

The first part we compared the responses to Ach and histamine before and after the addition of egg albumin in the control and sensitised tissue. It was made as a % of the pre-treatment response. We can see by this graph that all the responses were almost the same even in the control and the sensitised group.

[pic 1]

Preparation 1 part 2

           In part 2 we compared the response of Sensitised group to addition of egg albumin in two moments and also compared the response of control group to first addition of egg albumin and in a second time the addition of transfer liquid from the sensitised group. It was measured in grams tension from the pre-egg albumin baseline.

[pic 2]

We can see that in control group the response after the addition of the transfer liquid was higher than the addition of Egg albumin. However, in the sensitised group the response to the second addition of egg albumin was very small when compared to the first addition.

Preparation 2

Preparation 2 was divided in 4 parts.

Preparation 2 part 1

In this part was measured the responses to Ach and Histamine before and after the addition of Mepyramine, Indomethacin, both of them and the Vehicle. It was made as a percentage of t he pre-treatment response

[pic 3]

          As a result we can see that the Vehicle did not have any signifiable change in its responses. However, the Mepyramine group had a big response in the addition of Ach and a very low response of addition of Histamine and the group “Mepyramine + Indomethacin”, had a similar response as well. Nevertheless, the Indomethacin group had a opposite response, the Ach response was smaller than the Histamine one.

Preparation 2 part 2

In this part, we measured in grams tension the response to egg albumin in the presence of the treatments groups.

[pic 4]

          In this graph we can see that the vehicle had a response around 2g of tension and all the other groups had lower results. The smaller one was the Mepyramine + Indomethacine group, followed by the Mepyramine group and the Indomethacin group that has a little bit less than 2g tension.

Preparation 2 part 3

In this part we measured the time to maximum response in seconds of all treatment groups.

[pic 5]

We can observe that both groups Mepyramine and Mepyramine + Indomethacin had similar responses and they were bigger than the vehicle and Indomethacin groups, that also had similar responses.

Preparation 2 part 4

In this last part we compared the responses to egg albumin as “area under the curve”, AUC (g.sec) of all treatment groups.

[pic 6]

All groups had different results. The biggest response was from the vehicle group and the smaller one was from the Mepyramine+ Indomethacin group.

Discussion

Preparation 1

          In the first part of preparation 1 we can see that there is no significant difference between control and sensitised group in response to Ach or Histamine. It is expected, once this autacoids have nothing to do to the allergic reaction and also means that the tissue is viable.

         When we analyse the second part we can see that in the control group there was a very low response to the egg albumin addition. None response is expected, once the tissue is not allergic to the egg albumin. This little tension can be attributed to the normal function of the muscle. However, when we added the transfer liquid to the control, it had a really bigger response. It happened because we added with the fluid the autacoids, prostaglandins and all what a immune response involves. So it is not a contraction because of the production of a immune response from the muscle, but just the response of the muscle to the transfer’s elements.

In the other hand, when we added egg albumin for the first time to the sensitized tissue it had already a big response. It happened because the tissue was already sensitised what means that the antigen was presented to the lymphocytes earlier and the antibodies(IgE) were produced by this time. The IgE cells have already bound to the surface of mast cells and basophils, wich are both involved in the inflammatory response. When we added the first egg albumin it was like the second exposure and the allergen bound to the IgE molecules and held on the surface of the mast cells. It activated the mast cells and the degranulation began, becoming to release Histamine, prostaglandins and other inflammatory mediators and muscle contraction by that.