Inhibition of endogenous ouabain by atrial natriuretic peptide is a guanylyl cyclase independent effect.

BACKGROUND: Endogenous ouabain (EO) and atrial natriuretic peptide (ANP) are important in regulation of sodium and fluid balance. There is indirect evidence that ANP may be involved in the regulation of endogenous cardenolides. METHODS: H295R are human adrenocortical cells known to release EO. Cells were treated with ANP at physiologic concentrations or vehicle (0.1% DMSO), with or without guanylyl cyclase inhibitor 1,2,4 oxadiazolo[4,3-a]quinoxalin-1-one (ODQ). Cyclic guanosine monophosphate (cGMP), the intracellular second messenger of ANP, was measured by a chemiluminescent immunoassay and EO was measured by radioimmunoassay of C18 extracted samples. RESULTS: EO secretion is inhibited by ANP treatment, with the most prolonged inhibition (90 min vs ≤ 60 min) occurring at physiologic ANP concentrations (50 pg/mL). Inhibition of guanylyl cyclase with ODQ, also reduces EO secretion. The inhibitory effects on EO release in response to cotreatment with ANP and ODQ appeared to be additive. CONCLUSIONS: ANP inhibits basal EO secretion, and it is unlikely that this is mediated through ANP-A or ANP-B receptors (the most common natriuretic peptide receptors) or their cGMP second messenger; the underlying mechanisms involved are not revealed in the current studies. The role of ANP in the control of EO synthesis and secretion in vivo requires further investigation.

Inhaled loxapine for acute agitation in a psychiatric emergency service.

BACKGROUND: Rapid control of agitation in medical settings is necessary for safety and provision of care. Inhaled loxapine achieves peak plasma levels within 2 minutes of administration and is FDA-approved for managing acute agitation. METHODS: We examined the use of inhaled loxapine vs non-parenteral treatment as usual (TAU) in a psychiatric emergency service for consecutive patients with acute agitation or aggression. Data were collected retrospectively. T tests were used for continuous variables and Chi-square tests were used for categorical data. RESULTS: A total of 61 patients received inhaled loxapine and 29 received TAU. Time to outcome for patients receiving inhaled loxapine was 21 ± 21 minutes compared with 121 ± 206 minutes for TAU (t =-2.61; P = .014). At outcome, 89% of patients treated with loxapine experienced symptom resolution, compared with 69% of TAU (Chi-square = 17.4, P < .0001). Ten percent of patients receiving loxapine had no change in symptoms and 1% had worsening symptoms vs 14% in the TAU group who experienced no change in symptoms (z = 0.5, not significant), and 17% who described worsening symptoms (z = 6153.9, P < .0001). CONCLUSIONS: The rapid absorption of inhaled loxapine is associated with a 6-fold faster and more robust symptom control.

Effective Vortioxetine Dose Varies with Extent of Antidepressant Use Across Countries.

Objective: One of the possible explanations for the antidepressant resistance is tolerance to the effect of increasing synaptic serotonin. Vortioxetine is thought to work through a combination of two pharmacological modes of action: serotonin reuptake inhibition and modification of serotonin receptor activity, in a dose-dependent manner. This mechanism of action allows for examination of the hypothesis that antidepressant non-response may be due to exposure to persistently elevated synaptic amine levels. Methods: We hypothesized that lower doses of vortioxetine, which exclusively inhibit serotonin reuptake, would not be effective in the setting of prolonged exposure to antidepressants, but higher doses, which interact in various ways to multiple post-synaptic serotonin receptors, would be relatively more effective in the setting of prolonged, prestudy antidepressant exposure. We examined the relationship between Defined Daily Dose (DDD), which is a measure of the extent of antidepressant use in each country, and the minimal effective dose of vortioxetine. Principal Observation: There is a significant relationship between the DDD and effective vortioxetine dose (P = 0.035). Conclusions: In countries with high antidepressant utilization, higher doses of vortioxetine were required, and obverse was true in countries with lower antidepressant utilization. These data support the hypothesis that tolerance to serotonin reuptake inhibition drives poor antidepressant response.

E-Cigarette Toxicity?

Tobacco smoking is the most preventable cause of morbidity and mortality. In just a few short years, electronic cigarettes (e-cigarettes) have become increasingly popular, especially for younger individuals. Many people believe that e-cigarettes are safe. The inhaled aerosols of e-cigarettes contain numerous potential toxicities, some of which could be dangerous for health with long-term use. The safety of prolonged aerosol exposure is not known. The use of e-cigarettes as a harm-reduction tool at stopping tobacco smoking is not uniformly successful. E-cigarettes may be safer than tobacco products, but repeated prolonged exposure to their aerosols has its own considerable potential risk. The long-term health consequences of their use remain to be established. Physicians should vigorously discourage the use of e-cigarettes and tobacco products, with special emphasis on abstinence for younger people and during pregnancy or lactation.

Electroconvulsive Therapy During Pregnancy.

Women often experience worsening mood disorder symptoms during pregnancy. Women with mood disorders have an increased risk for suboptimal prenatal care, inadequate weight gain, and more substance abuse during pregnancy. It is often difficult to balance pharmacotherapy risks to a developing fetus versus not medicinally treating maternal mental health conditions. Electroconvulsive therapy (ECT) is a rapid and effective treatment option that can be an appropriate intervention in some women during pregnancy. This report presents an overview of ECT in pregnancy and the case of a 28-year-old pregnant woman with bipolar mania who responded well to ECT.