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 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.

Although a personally defined experience, successful breastfeeding is usually measured with regard to duration. This study investigated the determinants of maternal satisfaction with breastfeeding experience for 907 mothers enrolled in a prospective cohort study. Despite a median breastfeeding duration (18 weeks) that fell short of recommendations, 822 mothers (90.6%) rated their breastfeeding experience as very or fairly satisfactory. Anticipated breastfeeding duration was a determinant of satisfaction only for women who actually breastfeed < 2 months; in this subgroup of mothers, satisfaction rates ranged from 84.6% for those who anticipated breastfeeding < 2 months to 69.8% for those who anticipated breastfeeding > 4 months (P = .01). Smoking during pregnancy and experiencing breastfeeding difficulties after discharge were independently associated with decreased satisfaction. Eliciting the mother's expectations regarding breastfeeding duration may help the lactation consultant in providing appropriate guidance. Future studies should assess maternal satisfaction using validated instruments.

The present study investigated whether baroreflex control of autonomic function is impaired when there is a deficiency in NO production and the role of adrenergic and cholinergic mechanisms in mediating reflex responses. Electrical stimulation of the aortic depressor nerve in conscious normotensive and nitro-l-arginine methyl ester (L-NAME)-induced hypertensive rats was applied before and after administration of methylatropine, atenolol, and prazosin alone or in combination. The hypotensive response to progressive electrical stimulation (5 to 90 Hz) was greater in hypertensive (-27 ± 2 to -64 ± 3 mmHg) than in normotensive rats (-17 ± 1 to -46 ± 2 mmHg), whereas the bradycardic response was similar in both groups (-34 ± 5 to -92 ± 9 and -21 ± 2 to -79 ± 7 beats/min, respectively). Methylatropine and atenolol showed no effect in the hypotensive response in either group. Methylatropine blunted the bradycardic response in both groups, whereas atenolol attenuated only in hypertensive rats. Prazosin blunted the hypotensive response in both normotensive (43%) and hypertensive rats (53%) but did not affect the bradycardic response in either group. Prazosin plus angiotensin II, used to restore basal arterial pressure, provided hemodynamic responses similar to those of prazosin alone. The triple pharmacological blockade abolished the bradycardic response in both groups but displayed similar residual hypotensive response in hypertensive (-13 ± 2 to -27 ± 2 mmHg) and normotensive rats (-10 ± 1 to -25 ± 3 mmHg). In conclusion, electrical stimulation produced a well-preserved baroreflex-mediated decrease in arterial pressure and heart rate in conscious l-NAME-induced hypertensive rats. Moreover, withdrawal of the sympathetic drive played a role in the reflex bradycardia only in hypertensive rats. The residual fall in pressure after the triple pharmacological blockade suggests the involvement of a vasodilatory mechanism unrelated to NO or deactivation of α(1)-adrenergic receptor.