title: Targeted neuronal nitric oxide synthase transgene delivery into stellate neurons reverses impaired intracellular calcium transients in prehypertensive rats.
abstract: Hypertension is associated with the early onset of cardiac sympathetic hyperresponsiveness and enhanced intracellular Ca(2+) concentration [Ca(2+)](i) in sympathetic neurons from both prehypertensive and hypertensive, spontaneously hypertensive rats (SHRs). Oxidative stress is a hallmark of hypertension, therefore, we tested the hypothesis that the inhibitory action of the nitric oxide-cGMP pathway on [Ca(2+)](i) transients is impaired in cardiac sympathetic neurons from the SHR. Stellate ganglia were isolated from young prehypertensive SHRs and age-matched normotensive Wistar-Kyoto rats. [Ca(2+)](i) was measured by ratiometric fluorescence imaging. Neurons from the prehypertensive SHR ganglia had a significantly higher depolarization evoked [Ca(2+)](i) transient that was also associated with decreased expression of neuronal nitric oxide synthase (nNOS), β1 subunit of soluble guanylate cyclase and cGMP when compared with the Wistar-Kyoto rat ganglia. Soluble guanylate cyclase inhibition or nNOS inhibition increased [Ca(2+)](i) in the Wistar-Kyoto rats but had no effect in SHR neurons. A nitric oxide donor decreased [Ca(2+)](i) in both sets of neurons, although this was markedly less in the SHR. A novel noradrenergic cell specific vector (Ad.PRSx8-nNOS/Cherry) or its control vector (Ad.PRSx8-Cherry) was expressed in sympathetic neurons. In the SHR, Ad.PRSx8-nNOS/Cherry-treated neurons had a significantly reduced peak [Ca(2+)](i) transient that was associated with increased tissue levels of nNOS protein and cGMP concentration compared with gene transfer of Ad.PRSx8-Cherry alone. nNOS inhibition significantly increased [Ca(2+)](i) after Ad.PRSx8-nNOS/Cherry expression. We conclude that artificial upregulation of stellate sympathetic nNOS via targeted gene transfer can directly attenuate intracellular Ca(2+) and may provide a novel method for decreasing enhanced cardiac sympathetic neurotransmission.
authors.affiliation: Department of Physiology, Anatomy and Genetics, University of Oxford, Burdon Sanderson Cardiac Science Centre and BHF Centre of Research Excellence, Oxford, United Kingdom. dan.li@dpag.ox.ac.uk
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: Natalia
authors.initials: N
authors.lastname: Nikiforova
authors.forename: Chieh-Ju
authors.initials: CJ
authors.lastname: Lu
authors.forename: Kate
authors.initials: K
authors.lastname: Wannop
authors.forename: Mary
authors.initials: M
authors.lastname: McMenamin
authors.forename: Chee-Wan
authors.initials: CW
authors.lastname: Lee
authors.forename: Keith J
authors.initials: KJ
authors.lastname: Buckler
authors.forename: David J
authors.initials: DJ
authors.lastname: Paterson
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D006152:Cyclic GMP / Q000235:genetics / Q000378:metabolism; D018014:Gene Transfer Techniques; D008297:Male; D009474:Neurons / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D058246:Prehypertension / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D019076:Transgenes
chemical_list: D052248:Nitric Oxide Synthase Type I; D006152:Cyclic GMP; D002118:Calcium