The effect of pyridostigmine (PYR) - an acetylcholinesterase inhibitor - on hemodynamics and cardiac autonomic control, was never studied in conscious myocardial infarcted mice. Telemetry transmitters were implanted into the carotid artery under isoflurane anesthesia. Seven to ten days after recovery from the surgery, basal arterial pressure and heart rate were recorded, while parasympathetic and sympathetic tone (ΔHR) was evaluated by means of methyl atropine and propranolol. After the basal hemodynamic recording the mice were subjected to left coronary artery ligation for producing myocardial infarction (MI), or sham operation, and implantation of minipumps filled with PYR or saline. Separate groups of anesthetized (isoflurane) mice previously (4 weeks) subjected to MI, or sham coronary artery ligation, were submitted to cardiac function examination. The mice exhibited an infarct length of approximately 12%, no change in arterial pressure and increased heart rate only in the 1st week after MI. Vagal tone decreased in the 1st week, while the sympathetic tone was increased in the 1st and 4th week after MI. PYR prevented the increase in heart rate but did not affect the arterial pressure. Moreover, PYR prevented the increase in sympathetic tone throughout the 4 weeks. Concerning the parasympathetic tone, PYR not only impaired its attenuation in the 1st week, but enhanced it in the 4th week. MI decreased ejection fraction and increased diastolic and systolic volume. Therefore, the pharmacological increase of peripheral acetylcholine availability by means of PYR prevented tachycardia, increased parasympathetic and decreased sympathetic tone after MI in mice.
1 December 2019 in Advances in Physiology Education
Over the years, much criticism against animal use for physiology teaching has been made. Hence, replacement by suitable alternatives has increased in several pedagogical approaches. This study examined students’ perceptions of animal versus virtual (video/computer) laboratory classes in physiological sciences associated with the effectiveness of the problem-based learning (PBL) hybrid curriculum. Three cohorts of medical students from the University of Ribeirão Preto, who participated in animal or virtual physiology classes or both, were asked to fill out a 5-point Likert questionnaire about knowledge acquisition/motivation, importance to PBL learning goals, skills acquired, need for animal use, academic formation, learning impairment, and alternative methods. We also assessed their grades in the final exam. A total of 350 students were included, in which 108 participated only in virtual classes, 120 only in practical animal laboratory classes, and 122 in both approaches. The majority agreed that the two methods improved their knowledge acquisition/motivation and helped to reinforce tutorial goals and to acquire skills. However, the cohort who experienced both approaches favored animal laboratory. Students believe animal use is needed and did not impair their learning. Conversely, their opinion about academic formation without animal laboratory classes was divided, as was whether this approach inspired them to seek alternative methods. Despite the different perceptions, there was no difference among the groups’ final grades (7.3 ± 1 vs. 7.2 ± 1 vs. 7.2 ± 2 for virtual or practical animal laboratory classes or both, respectively). Therefore, virtual activities are not as effective as animal use in the opinions of the students, but they are successful strategies in physiology learning that can be used in practical classes in a hybrid PBL curriculum.
The regular practice of physical exercise as a non-pharmacological treatment of arterial hypertension (AH) has been encouraged due to causing a series of physiological responses in the cardiovascular system, such as the production of vasoactive substances, including nitric oxide (NO). NO is a relaxation factor released by the endothelium, and the decrease in its bioavailability is related to coronary and arterial diseases, such as AH. This study aimed to perform an integrative literature review to elucidate the effect of [...] Abstract The regular practice of physical exercise as a non-pharmacological treatment of arterial hypertension (AH) has been encouraged due to causing a series of physiological responses in the cardiovascular system, such as the production of vasoactive substances, including nitric oxide (NO). NO is a relaxation factor released by the endothelium, and the decrease in its bioavailability is related to coronary and arterial diseases, such as AH. This study aimed to perform an integrative literature review to elucidate the effect of