Nitric oxide synthase inhibition restores orthostatic tolerance in young vasovagal syncope patients.

ABSTRACT:

Objective

Syncope is sudden transient loss of consciousness and postural tone with spontaneous recovery; the most common form is vasovagal syncope (VVS). We previously demonstrated impaired post-synaptic adrenergic responsiveness in young VVS patients was reversed by blocking nitric oxide synthase (NOS). We hypothesised that nitric oxide may account for reduced orthostatic tolerance in young recurrent VVS patients.

Methods

We recorded haemodynamics in supine VVS and healthy volunteers (aged 15-27 years), challenged with graded lower body negative pressure (LBNP) (-15, -30, -45 mm Hg each for 5 min, then -60 mm Hg for a maximum of 50 min) with and without NOS inhibitor N^G-monomethyl-L-arginine acetate (L-NMMA). Saline plus phenylephrine (Saline+PE) was used as volu

SUBMITTER: Stewart JM 

PROVIDER: S-EPMC5819615 | biostudies-literature | 2017 Nov

REPOSITORIES: biostudies-literature