RESUMEN
OBJECTIVE: Puberty is a key developmental phenomenon highly sensitive to metabolic modulation. Worrying trends of changes in the timing of puberty have been reported in humans. These might be linked to the escalating prevalence of childhood obesity and could have deleterious impacts on later (cardio-metabolic) health, but their underlying mechanisms remain unsolved. The neuropeptide α-MSH, made by POMC neurons, plays a key role in energy homeostasis by mediating the actions of leptin and likely participates in the control of reproduction. However, its role in the metabolic regulation of puberty and interplay with kisspeptin, an essential puberty-regulating neuropeptide encoded by Kiss1, remain largely unknown. We aim here to unveil the potential contribution of central α-MSH signaling in the metabolic control of puberty by addressing its role in mediating the pubertal effects of leptin and its potential interaction with kisspeptin. METHODS: Using wild type and genetically modified rodent models, we implemented pharmacological studies, expression analyses, electrophysiological recordings, and virogenetic approaches involving DREADD technology to selectively inhibit Kiss1 neurons, in order to interrogate the physiological role of a putative leptinâα-MSHâkisspeptin pathway in the metabolic control of puberty. RESULTS: Stimulation of central α-MSH signaling robustly activated the reproductive axis in pubertal rats, whereas chronic inhibition of melanocortin receptors MC3/4R, delayed puberty, and prevented the permissive effect of leptin on puberty onset. Central blockade of MC3/4R or genetic elimination of kisspeptin receptors from POMC neurons did not affect kisspeptin effects. Conversely, congenital ablation of kisspeptin receptors or inducible, DREADD-mediated inhibition of arcuate nucleus (ARC) Kiss1 neurons resulted in markedly attenuated gonadotropic responses to MC3/4R activation. Furthermore, close appositions were observed between POMC fibers and ARC Kiss1 neurons while blockade of α-MSH signaling suppressed Kiss1 expression in the ARC of pubertal rats. CONCLUSIONS: Our physiological, virogenetic, and functional genomic studies document a novel α-MSHâkisspeptinâGnRH neuronal signaling pathway involved in transmitting the permissive effects of leptin on pubertal maturation, which is relevant for the metabolic (and, eventually, pharmacological) regulation of puberty onset.
RESUMEN
Resumen
Introducción: en la formación de la enfermera, la teoría se complementa con la práctica, situación en la cual el estrés se encuentra presente.
Objetivo: evaluar una intervención de apoyo a estudiantes de enfermería en su primera práctica clínica para afrontar situaciones de estrés.
Metodología: estudio cuasi-experimental de prueba y posprueba. Se incluyeron estudiantes de segundo semestre de licenciatura en enfermería, ciclo 2011-2012. Se aplicó el cuestionario KEZKAZ (2003) para identificar situaciones estresantes, posteriormente se realizó una intervención de apoyo durante la práctica clínica en la que se manejaron competencias y contención de emociones. El análisis estadístico se realizó con la prueba de Wilcoxon para población pareada. A los participantes en el estudio se les solicitó consentimiento informado y se garantizó la confiabilidad de la información. Resultados: en relación con las dimensiones que conforman el KEZKAZ, se encontró significancia estadística (p < 0.05) para relaciones con tutores y compañeros, impotencia e incertidumbre ante la atención directa al paciente y sobrecarga de trabajo.
Conclusión: se encontró modificación en la percepción de los estudiantes posterior a la intervención, mostrando mayor autonomía y mayor certidumbre en su actuar, así como disminución en la percepción de sobrecarga de trabajo. Es necesario un mayor tiempo de apoyo para lograr modificar dimensiones que implican la relación enfermero-paciente.
Abstract
Introduction: In nursing, professional training practice complements theory, and it is an event where stress is often involved.
Objective: To assess a support intervention for nursing students in order to face situations of stress during their first clinical practice.
Methods: Test and post-test quasi-experimental study including undergraduate students from second semester of nursing bachelor, school year 2011-2012. KEZKAZ (2003) questionnaire was applied in order to identify stress situations; then a support intervention was performed during clinical practice in which competences and handling of emotional situations were practiced. Statistical analysis was performed through Wilcoxon Rank Test for paired population. Participants were requested for their informed consent and information reliability was ensured.
Results: Regarding dimensions conforming KEZKAZ questionnaire, statistical significance (p < 0.05) was found for relationships among tutors and their partners, discomfort and uncertainty about direct health care to patients and overload of work.
Conclusions: A change in perception of students after the intervention was found, showing greater autonomy and greater certainty in their performance, as well as a reduction in the work overload perception. A great deal of support time is required in order to change dimensions involving the nurse to patient relationship.