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. 2016 Aug 16;11(8):e0160813. doi: 10.1371/journal.pone.0160813

Fig 1. NOS-1 inhibition reduces the inotropic response to β-adrenergic stimulation.

Fig 1

(A) Contractility (dP/dtmax) values obtained consecutively under basal conditions (Basal), stimulation with isoproterenol (10nM, 3-min) (Iso); recovery after 10-min washout of the agonist (Rec.), and after 20-min treatment (Treat.) with vehicle (Control, n = 14), or NOS-1 inhibitors L-Methyl-thio-citrulline 300nM (SMTC, n = 8), or Nω—propyl—L—arginine 200nM (LNPA, n = 6), or NOS-3 inhibitor L-N5-(1-Iminoethyl)ornithine 1μM (LNIO, n = 6). Asterisk indicates p<0.05 vs. respective Basal (paired t test, with Dunnett’s modification). (B) Accumulative concentration-response curves to isoproterenol in absence (Control) or presence of NOS-1 inhibitors SMTC or LNPA, or NOS-3 inhibitor LNIO (‡ p<0.001 vs. Control curve, best fit ANOVA, the difference resided only in the top value; bottom and EC50 parameters were shared). (C) Same data as in panel B, expressed as relative values, corrected by the corresponding contractility values after treatment with inhibitor. (* p<0.05 (LNPA), † p<0.01 (SMTC, LNIO) vs. control curve; the difference resided in the top value). (D) Representative records showing contractility (dP/dt) responses elicited by application of Iso10nM (solid line) before and after treatment with SMTC (top) and LNIO (bottom). The dashed line indicates application of 100nM Iso as part of the dose-response curve.