Fredrickson, Paul

Background: Ambulatory blood pressure monitoring (ABPM) is important for the diagnosis of hypertension (HTN) as well as variants such as nocturnal HTN (NH), masked HTN and a non-dipping pattern. NH and non-dipping, a failure of the normal circadian drop in blood pressure during sleep, have been associated with all-cause mortality and cardiovascular risk. Obstructive sleep apnea is associated with HTN and a growing body of evidence suggests that limb movement disorders of sleep may also influence cardiovascular morbidity. The present study investigates arousals of sleep disorders, limb movement or respiratory, and their relationship to ABPM measurements. Methods: A retrospective review (January 1, 2010 to December 31, 2014) was performed on patients that underwent both ABPM and polysomnography within a six months of each other. Socio-demographic data, results of 24 hour ABPM and polysomnography, concurrent medication use by class, comorbid conditions and laboratory data were recorded. Patients with incomplete polysomnography or ABPM measurements were excluded. Results: 330 individuals met criterion for inclusion; 59% male, 86% white. 211 (64%) were found to have NH, 106 (32%) had uncontrolled HTN and 202 (61%) had a non-dipping pattern. Patients with NH were more likely to have diabetes, hyperlipidemia and chronic kidney disease. Elevated arousal indices were more prevalent in those with NH, uncontrolled HTN and non-dippers. There was an association of NH with the total number of arousals per hour of sleep (p<0.01), whether related to respiratory disturbances or limb movements. Limb movement index (LMI) was related to age (p<0.0001) and was associated with all type arousals (p<0.0001). Conclusions: ABPM revealed a high prevalence of NH, non-dipping, masked and uncontrolled HTN in patients with sleep disorders. Arousals of all types, whether accompanying respiratory or limb movements, were associated with NH and also with LMI.

Neurotensin (NT) is a neuropeptide that is closely associated with, and is thought to modulate, dopaminergic and other neurotransmitter systems involved in the pathophysiology of various mental disorders. This review outlines data implicating NT in the pathophysiology and management of major mental disorders such as schizophrenia, drug addiction, and autism. The data suggest that NT receptor analogs have the potential to be used as novel therapeutic agents acting through modulation of neurotransmitter systems dys-regulated in these disorders.

Tobacco usage typically precedes illicit drug use in adolescent and young adult populations. Several animal studies suggest nicotine increases the risk for subsequent cocaine abuse, and may be a negative prognostic factor for treatment of cocaine addiction; i.e., a “gateway drug”. Neurotensin (NT) is a 13-amino acid neuropeptide that modulates dopamine, acetylcholine, glutamate, and GABA neurotransmission in brain reward pathways. NT69L, a NT(8-13) analog, blocks behavioral sensitization (an animal model for psychostimulant addiction) to nicotine, and nicotine self-administration in rats. The present study tested the effect of NT69L on the potentiating effects of nicotine on cocaine-induced locomotor sensitization. Male Wistar rats were injected daily for seven days with nicotine or saline (control) followed by four daily injections of cocaine. NT69L was administered 30 min prior to the last cocaine injection. Behavior was recorded with the use of activity chambers. Subchronic administration of nicotine enhanced cocaine-induced behavioral sensitization in Wistar rats, consistent with an hypothesized gateway effect. These behavioral effects of cocaine were attenuated by pretreatment with NT69L. The effect of the neurotensin agonist on cocaine sensitization in the nicotine treated group indicated a possible therapeutic effect for cocaine addiction, even in the presence of enhanced behavioral sensitization induced by nicotine.