The Effect of Hormones and Neurotransmitters on the Uterus and Small Intestine Muscles

In this experiment, two independent variables were investigated. The effects of calcium ion concentration and hormone/neurotransmitter in the uterus and small intestine muscle were measured. The baseline or control was established using BIOPAC. We were able to recorder five spontaneous contractions which acted as our control measurement for each tissue.

Hormone and Neurotransmitter Effects

We were provided with one neurotransmitter (acetylcholine) and two hormones (epinephrine and oxytocin) as stock solutions in physiological buffer. The acetylcholine, epinephrine, and oxytocin stock solutions contained 5, 20, and 5 mg of the individual solutions per milliliter of the buffer. It should be noted that the test chamber was initially filled with 60 ml of working volume but during the experiment, an amount of 5 ml was removed before the application of each drug. The data were collected for at least five complete contraction cycles for 5 minutes. We then replaced the working volume in the testing chamber with fresh oxygenated buffer before recording control for the next part of this experiment. Moreover, tissues were allowed between 3 – 5 minutes to re-equilibrate in the buffer.

Effect of Changes in Calcium Concentration

In the bid to determine the effect of calcium concentration on the muscle, we first recorded several contractions in normal rat saline. After that, we added some Ca2+-free ringers to the testing chamber to reduce the concentration of calcium to the muscles. We recorded several contractions every time we altered the concentration of calcium ions.

Effect of hypoxia

After performing the two experiments above, we removed the aeration line to eliminate oxygen from the tissue. Besides, the buffer was replaced with standard rat saline for the tissue to recover from lack of calcium. We then recorded our recovery process after muscles had relaxed for 10 – 20 minutes after removing the aeration line.