1.Monitoring of in vivo manipulation of nitric oxide synthases at the rat retina using the push-pull perfusion sampling and capillary electrophoresis.
Pritchett JS1, Shippy SA2. J Chromatogr B Analyt Technol Biomed Life Sci. 2014 Apr 1;955-956:81-5. doi: 10.1016/j.jchromb.2014.02.022. Epub 2014 Feb 22.
Proteins play a variety of functional roles in tissues that underlie tissue health. The measurement of protein function is important to both understand normal and dysfunctional tissue states. Low-flow push-pull perfusion sampling (LFPS) has been used to collect submicroliter volumes of extracellular fluid which are well suited to capillary electrophoresis for compositional quantitative analysis. In this study, LFPS is used to deliver pharmacological agents to the in vivo retinal tissues at the probe sampling tip during sampling to measure protein function. Two native nitric oxide synthase enzymes were pharmacologically inhibited and the enzyme product NO metabolite, nitrate, was determined with capillary electrophoresis from the perfusates. LFPS delivered inhibitors including the non-selective N(G)-nitro-Larginine methyl ester (L-NAME), the nNOS selective 7-nitroindazole (7-NI), and eNOS N5-(1-imioethyl)-L-ornithine, dihydrochloride (L-NIO) were perfused to the sampling region either directly over a rat retina optic nerve head or 1-mm peripheral to the ONH.
2.Phosphodiesterase 5 inhibitors prevent 3,4-methylenedioxymethamphetamine-induced 5-HT deficits in the rat.
Puerta E1, Hervias I, Goñi-Allo B, Lasheras B, Jordan J, Aguirre N. J Neurochem. 2009 Feb;108(3):755-66. doi: 10.1111/j.1471-4159.2008.05825.x.
Phosphodiesterase 5 (PDE5) inhibitors are often used in combination with club drugs such as 3,4-methylenedioxymethamphetamine (MDMA or ecstasy). We investigated the consequences of such combination in the serotonergic system of the rat. Oral administration of sildenafil citrate (1.5 or 8 mg/kg) increased brain cGMP levels and protected in a dose-dependent manner against 5-hydroxytryptamine depletions caused by MDMA (3 x 5 mg/kg, i.p., every 2 h) in the striatum, frontal cortex and hippocampus without altering the acute hyperthermic response to MDMA. Intrastriatal administration of the protein kinase G (PKG) inhibitor, KT5823 [(9S, 10R, 12R)-2,3,9,10,11,12-Hexahydro-10-methoxy-2,9-dimethyl-1-oxo-9,12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-i][1,6]benzodiazocine-10-carboxylic acid, methyl ester)], suppressed sildenafil-mediated protection. By contrast, the cell permeable cGMP analogue, 8-bromoguanosine cyclic 3',5'-monophosphate, mimicked sildenafil effects further suggesting the involvement of the PKG pathway in mediating sildenafil protection.
3.Adenosine produces nitric oxide and prevents mitochondrial oxidant damage in rat cardiomyocytes.
Xu Z1, Park SS, Mueller RA, Bagnell RC, Patterson C, Boysen PG. Cardiovasc Res. 2005 Mar 1;65(4):803-12.
OBJECTIVE: To examine if adenosine prevents oxidant-induced mitochondrial dysfunction by producing nitric oxide (NO) in cardiomyocytes.
4.Endothelial nitric oxide synthase mediates the nitric oxide component of reflex cutaneous vasodilatation during dynamic exercise in humans.
McNamara TC1, Keen JT1, Simmons GH2, Alexander LM3, Wong BJ4. J Physiol. 2014 Dec 1;592(23):5317-26. doi: 10.1113/jphysiol.2014.272898. Epub 2014 Sep 25.
Recent data suggests neuronal nitric oxide synthase (nNOS) mediates the NO component of reflex cutaneous vasodilatation with passive heat stress. We tested the hypothesis that nNOS inhibition would attenuate reflex cutaneous vasodilatation during sustained dynamic exercise in young healthy humans. All subjects first performed an incremental V̇O2, peak test to exhaustion on a custom-built supine cycle ergometer. On a separate day, subjects were instrumented with four intradermal microdialysis fibres on the forearm and each randomly assigned as: (1) lactated Ringer's (control); (2) 20 mm Nω-nitro-l-arginine methyl ester hydrochloride (non-selective NOS inhibitor); (3) 5 mm N-propyl-l-arginine (nNOS inhibitor); and (4) 10 mm N(5)-(1-iminoethyl)-l-ornithine dihydrochloride [endothelial NOS (eNOS) inhibitor]. Following microdialysis placement, subjects performed supine cycling with the experimental arm at heart level at 60% V̇O2, peak for a period sufficient to raise core temperature 0.
