C57BL/6J and DBA/2J strains present opposite sex differences in flash visual evoked potential latency: a possible confusing factor in gender studies on neurological diseases' transgenic models

The cholinergic neurotransmitter system in the brain is crucial in processing information related to cognitive, behavioral, and motor functions. A cholinergic dysfunction has been correctly described as one of the primary causes of neurodegenerative diseases. Differences in levels of acetylcholine or expression and function of receptors in selected brain areas have been indicated as one of the causes of sexual dimorphism in neurotransmission. However, variability in results among studies based on different mice strains could affect conclusions on this topic. Visual evoked potentials (VEPs) of male and female DBA/2J and C57BL/6J mice, which are two of the most common strains backgrounds in use for developing transgenic mice models of neurological diseases, have been studied. Effects induced by a single low dose of physostigmine have also been performed to evaluate the cholinergic system involvement. VEPs responses to luminous stimuli in C57BL/6J mice have shown a consistently lower latency than in DBA/2J, confirming the previous observation of strain differences in cholinergic function. Interestingly, strains present an opposite-sex difference in VEP latency not apparently related to sensitivity to physostigmine. These findings point at paying extreme attention to the choice of the genetic background of the animal model, especially in those basic and pre-clinical experiments that involve visual functioning

IL PEPTIDE VASOATTIVO INTESTINALE NELLO SCOMPENSO CARDIACO.

BACKGROUND: The aim of our study was to investigate the pathophysiological role of the vasoactive intestinal peptide (VIP), a vasodilating neuropeptide with positive inotropic and chronotropic properties, in heart failure. METHODS: The study was carried out in 35 patients with heart failure due to dilated cardiomyopathy, who underwent a peripheral venous blood sample for radioimmunoassay of VIP within the first in-hospital day. RESULTS: The plasma concentration of VIP: 1) is not higher than normal in the whole group of patients with heart failure; 2) is higher in younger than in elderly healthy subjects but does not significantly change in relation to age in heart disease patients; 3) is higher in elderly (> 60 years) but not in younger ( 2 groups and in normal subjects; 5) is not correlated with echocardiographic parameters; 6) does not significantly change with respect to the etiology of dilated cardiomyopathy. CONCLUSIONS: The plasma concentration of VIP in heart failure is conditioned by some epidemiological and clinical variables. Unlike the healthy group, differences are not detectable with respect to the age of patients; thus, in elderly heart disease subjects the neuropeptide productive potentiality is preserved. Taking into account the physiological properties of VIP, its plasma increase in the initial phase of heart failure can be reasonably regarded as a further mechanism to restore the compromised hemodynamic balance. Its decrease, related to worse clinical conditions, could be due to a progressive depletion from the pre-synaptic nerve endings and to a deficiency in the neurogenic productive capacity of the molecule