RESUMEN
Sleep disorders affect millions of people around the world and have a high comorbidity with psychiatric disorders. While current hypnotics mostly increase non-rapid eye movement sleep (NREMS), drugs acting selectively on enhancing rapid eye movement sleep (REMS) are lacking. This polysomnographic study in male rats showed that the first-in-class selective melatonin MT1 receptor partial agonist UCM871 increases the duration of REMS without affecting that of NREMS. The REMS-promoting effects of UCM871 occurred by inhibiting, in a dose-response manner, the firing activity of the locus ceruleus (LC) norepinephrine (NE) neurons, which express MT1 receptors. The increase of REMS duration and the inhibition of LC-NE neuronal activity by UCM871 were abolished by MT1 pharmacological antagonism and by an adeno-associated viral (AAV) vector, which selectively knocked down MT1 receptors in the LC-NE neurons. In conclusion, MT1 receptor agonism inhibits LC-NE neurons and triggers REMS, thus representing a novel mechanism and target for REMS disorders and/or psychiatric disorders associated with REMS impairments.
Asunto(s)
Locus Coeruleus , Ratas Sprague-Dawley , Receptor de Melatonina MT1 , Sueño REM , Animales , Masculino , Locus Coeruleus/efectos de los fármacos , Locus Coeruleus/metabolismo , Locus Coeruleus/fisiología , Ratas , Receptor de Melatonina MT1/agonistas , Receptor de Melatonina MT1/metabolismo , Sueño REM/fisiología , Sueño REM/efectos de los fármacos , Norepinefrina/metabolismo , Neuronas Adrenérgicas/efectos de los fármacos , Neuronas Adrenérgicas/metabolismo , Neuronas Adrenérgicas/fisiología , Neuronas/metabolismo , Neuronas/efectos de los fármacos , Neuronas/fisiologíaRESUMEN
Suicide was the secondleading cause of US deaths in 2018 among 15-24-year-olds. Suicide attempts, a risk factor for completions, and suicide ideation have doubled among pediatric emergency room (ER) patients during the past decade. Borderline Personality Disorder (BPD), a comorbid condition, has a 10% suicide rate. We examined the 4-year outcome of a cohort of suicidal adolescents, many also suffering from BPD and having undergone some form of treatment, to identify baseline factors which could inform intervention that would minimize suicidality 4 years post-discharge. METHODS: We conducted a prospective longitudinal study of suicidality at twelve points (four assessment occasions) for 286 suicidal youth presenting to a pediatric ER, most suffering from BPD, with 36 suicide ratings from baseline to 2-, 6- and 48-month follow-up evaluations. We examined the trajectory and predictors of persisting suicidality. RESULTS: Suicidality rapidly decreased within 2 months post-ER-discharge, subsequently remaining low throughout 48 months. Baseline functioning, female sex, stressful life events and BPD impulsiveness were most predictive of persisting suicidality at 48-month follow-up. CONCLUSION: Most suicidal youth, many meeting BPD criteria, no longer feel suicidal 2 months after ER discharge. Management of participants' baseline poor functioning stressful life events and the impulsiveness component of BPD specifically in females could impact suicidality 4 years later, and guide treatment options. The absence of the BPD cognitive and affective subscales as predictors of suicidality at 4-year follow-up may reflect treatment received. Further investigation of treatment effects is warranted and under way.