Contractile Effects of Amphetamine, Pseudoephedrine, Nor-pseudoephedrine (Cathine), and Cathinone on Atrial Preparations of Mice and Humans.

ABSTRACT: Amphetamine derivatives are used worldwide legally or illegally and intoxications may be accompanied by cardiac arrhythmias. Here, we tested contractile effects of cumulative applied (±)-amphetamine, pseudoephedrine, nor-pseudoephedrine (cathine), and cathinone in electrically stimulated (1 Hz) human right atrial preparations (HAP) and mouse left atrial preparations and in spontaneously beating mouse right atrial preparations. In mouse atrial preparations, amphetamine increased force of contraction and beating rate in a concentration- and time-dependent manner, starting at 1 µM in left atrial preparations to 157.1% ± 3.0% and right atrial preparations to 146.6% ± 9.8% at 10 µM, respectively [mean ± standard error of the mean (SEM); n = 5; P < 0.05]. Pseudoephedrine, cathine, or cathinone alone were ineffective in mouse atrial preparations but after pre-incubation with the phosphodiesterase IV inhibitor rolipram (0.1 µM), a positive inotropic effect was noted (mean ± SEM: pseudoephedrine: 112.3% ± 9.8%; cathine: 109.0% ± 4.3%; cathinone: 138.3% ± 21.2%). The effects of all drugs were greatly attenuated by 10 µM cocaine or 10 µM propranolol treatments. However, In HAP, not only amphetamine (to a mean ± SEM of 208% ± 32%) but also pseudoephedrine (to a mean ± SEM of 287% ± 60%), cathine (to a mean ± SEM of 234% ± 52%), and cathinone (to a mean ± SEM of 217% ± 65%) increased force of contraction without the need of phosphodiesterase inhibition. The contractile effects in HAP were attenuated by 10 µM cocaine and antagonized by 10 µM propranolol. We conclude that amphetamine, pseudoephedrine, cathine, and cathinone act probably via release of noradrenaline from cardiac stores as indirect sympathomimetic agents in mouse and more pronounced in human atrial preparations.

Extracellular Matrix Changes in Subcellular Brain Fractions and Cerebrospinal Fluid of Alzheimer's Disease Patients.

The brain's extracellular matrix (ECM) is assumed to undergo rearrangements in Alzheimer's disease (AD). Here, we investigated changes of key components of the hyaluronan-based ECM in independent samples of post-mortem brains (N = 19), cerebrospinal fluids (CSF; N = 70), and RNAseq data (N = 107; from The Aging, Dementia and TBI Study) of AD patients and non-demented controls. Group comparisons and correlation analyses of major ECM components in soluble and synaptosomal fractions from frontal, temporal cortex, and hippocampus of control, low-grade, and high-grade AD brains revealed a reduction in brevican in temporal cortex soluble and frontal cortex synaptosomal fractions in AD. In contrast, neurocan, aggrecan and the link protein HAPLN1 were up-regulated in soluble cortical fractions. In comparison, RNAseq data showed no correlation between aggrecan and brevican expression levels and Braak or CERAD stages, but for hippocampal expression of HAPLN1, neurocan and the brevican-interaction partner tenascin-R negative correlations with Braak stages were detected. CSF levels of brevican and neurocan in patients positively correlated with age, total tau, p-Tau, neurofilament-L and Aß1-40. Negative correlations were detected with the Aß ratio and the IgG index. Altogether, our study reveals spatially segregated molecular rearrangements of the ECM in AD brains at RNA or protein levels, which may contribute to the pathogenic process.

Methamphetamine increases force of contraction in isolated human atrial preparations through the release of noradrenaline.

We measured the cardiac contractile effects of the sympathomimetic amphetamine-like drug methamphetamine alone and in the presence of cocaine or propranolol in human atrial preparations. For a more comprehensive analysis, we also examined the effects of methamphetamine in preparations from the left and right atria of mice and, for comparison, analyzed the cardiac effects of amphetamine itself. In human atrial preparations, methamphetamine and amphetamine increased the contractile force, the relaxation rate, and the rate of tension development, and shortened the time to maximum tension and the time to relaxation. Likewise, in mice preparations, methamphetamine and amphetamine increased the contractile force in the left atrium and increased the beating rate in the right atrium. The effect in human atrial preparations started at 1 µM, therefore methamphetamine was less effective and potent than isoproterenol in increasing contractile force. These positive inotropic effects of methamphetamine were greatly attenuated by 10 µM cocaine and abolished by 10 µM propranolol. The inotropic effects of methamphetamine in human atrial preparations were associated with, and are believed to be mediated at least in part by, an increase in the phosphorylation state of the inhibitory subunit of troponin. In conclusion, the sympathomimetic central stimulant drug methamphetamine (as well as amphetamine) increased contractile force and protein phosphorylation, presumably through a release of noradrenaline in isolated human atrial preparations. Thus, methamphetamine acts as an indirect sympathomimetic in the human atrium.

Brevican and Neurocan Cleavage Products in the Cerebrospinal Fluid - Differential Occurrence in ALS, Epilepsy and Small Vessel Disease.

The neural extracellular matrix (ECM) composition shapes the neuronal microenvironment and undergoes substantial changes upon development and aging, but also due to cerebral pathologies. In search for potential biomarkers, cerebrospinal fluid (CSF) and serum concentrations of brain ECM molecules have been determined recently to assess ECM changes during neurological conditions including Alzheimer's disease or vascular dementia. Here, we measured the levels of two signature proteoglycans of brain ECM, neurocan and brevican, in the CSF and serum of 96 neurological patients currently understudied regarding ECM alterations: 16 cases with amyotrophic lateral sclerosis (ALS), 26 epilepsy cases, 23 cerebral small vessel disease (CSVD) patients and 31 controls. Analysis of total brevican and neurocan was performed via sandwich Enzyme-linked immunosorbent assays (ELISAs). Major brevican and neurocan cleavage products were measured in the CSF using semiquantitative immunoblotting. Total brevican and neurocan concentrations in serum and CSF did not differ between groups. The 60 kDa brevican fragment resulting from cleavage by the protease ADAMTS-4 was also found unchanged among groups. The presumably intracellularly generated 150 kDa C-terminal neurocan fragment, however, was significantly increased in ALS as compared to all other groups. This group also shows the highest correlation between cleaved and total neurocan in the CSF. Brevican and neurocan levels strongly correlated with each other across all groups, arguing for a joint but yet unknown transport mechanism from the brain parenchyma into CSF. Conclusively our findings suggest an ALS-specific pattern of brain ECM remodeling and may thus contribute to new diagnostic approaches for this disorder.