Daphnia Lab Report
Receptors and Ligands: Examining the effects of pharmaceutical compounds on Daphnia magna physiology
Abstract
The following study was conducted in order to determine the effects of four different pharmaceutical compounds on the heart rate of Daphnia specimens. After basal heart rate was observed and computed, four different solutions each containing either an adrenergic, muscarinic, or nicotinic agonist or antagonist was tested against individual Daphnia. Observations were made through a compound light microscope through the 10x objective. It was found that nicotine decreased, caffeine increased, lidocaine decreased, epi decreased basal heart rate. This can be explained secondary to their effects as either receptor antagonists or agonists. …show more content…
For one, when sample size was n=3, there was a marked decrease heart rate for samples treated with nicotine from a basal heart rate of 147.04 bpm to a drug treated heart rate of 66.67 bpm which is contradictory to the literature and contradictory to experimental values when n=12. Nicotine is a known stimulant increasing blood pressure, heart rate, and myocardial contractility by activating the release of catecholamine by binding to nicotinic acetylcholine receptors on the adrenal medulla and postganglionic sympathetic nervous system [1]. Several possibilities may help explain this aberration. For one, the sample size may simply have been too small to accurately determine the effects of nicotine on heart rate. This possibility is supported by the experimental data of a larger sample size. Other possibilities exist such as experimenter error. For example, it is possible that not enough nicotine solution was added to induce a physiological reaction of the Daphnia specimens. Further, the Daphnia used when n=3 appeared to have a lower heart rate in general when compared to sample size n=12. This could indicate a Daphnia population that wasn’t healthy and, therefore, had a compromised metabolism and did not respond as a healthy Daphnia would. Future experimenters would do well to ensure that a large enough sample size was used and that the Daphnia population was in optimal
Abstract
The following study was conducted in order to determine the effects of four different pharmaceutical compounds on the heart rate of Daphnia specimens. After basal heart rate was observed and computed, four different solutions each containing either an adrenergic, muscarinic, or nicotinic agonist or antagonist was tested against individual Daphnia. Observations were made through a compound light microscope through the 10x objective. It was found that nicotine decreased, caffeine increased, lidocaine decreased, epi decreased basal heart rate. This can be explained secondary to their effects as either receptor antagonists or agonists. …show more content…
For one, when sample size was n=3, there was a marked decrease heart rate for samples treated with nicotine from a basal heart rate of 147.04 bpm to a drug treated heart rate of 66.67 bpm which is contradictory to the literature and contradictory to experimental values when n=12. Nicotine is a known stimulant increasing blood pressure, heart rate, and myocardial contractility by activating the release of catecholamine by binding to nicotinic acetylcholine receptors on the adrenal medulla and postganglionic sympathetic nervous system [1]. Several possibilities may help explain this aberration. For one, the sample size may simply have been too small to accurately determine the effects of nicotine on heart rate. This possibility is supported by the experimental data of a larger sample size. Other possibilities exist such as experimenter error. For example, it is possible that not enough nicotine solution was added to induce a physiological reaction of the Daphnia specimens. Further, the Daphnia used when n=3 appeared to have a lower heart rate in general when compared to sample size n=12. This could indicate a Daphnia population that wasn’t healthy and, therefore, had a compromised metabolism and did not respond as a healthy Daphnia would. Future experimenters would do well to ensure that a large enough sample size was used and that the Daphnia population was in optimal