title: [Hemodynamic actions of N-nitro-L-arginine and its effect on renal sympathetic nerve activity in anesthetized rats].
abstract: The hemodynamic actions of N-nitro-L-arginine (L-NNA), a novel NO synthesis inhibitor, and its effect on renal sympathetic nerve activity (RSNA) were examined in anesthetized rats to define the possible role of L-NNA in the regulation of blood pressure and the underlying mechanism(s). The results obtained were as follows. (1) Following intravenous bolus injection of L-NNA (15 mg/kg), MAP was changed from 9.87 +/- 0.80 to 14.67 +/- 0.53 kPa (P < 0.001), HR from 317 +/- 13 to 303 +/- 14 bpm, CI from 9.79 +/- 0.83 to 7.04 +/- 0.41 ml/min.100 g-1 (P < 0.05), and TPRI from 1.04 +/- 0.10 to 2.15 +/- 0.18 u/100 g (P < 0.001), all lasting for more than 30 min. The above-mentioned actions of L-NNA could be inhibited by prior administration of L-arginine (200 mg/kg). (2) In rats with sinoaortic denervation (SAD), i.v. L-NNA might induce an increase in HR, indicating that L-NNA-induced bradycardia was resulted from a baroreceptive activation. (3) In rats with buffer nerves intact, i.v. L-NNA failed to induce a significant change in RSNA, though an increase in MAP accompanied by bradycardia was observed. (4) With i.v. L-NNA for SAD rats, MAP, HR and RSNA were markedly increased by 55.6%, 5.1% and 34.3%, respectively. The results implied that L-NNA was able to activate sympathetic center, and L-NNA-induced change of RSNA could be masked by baroreflex. Prior administration of L-arg was capable of inhibiting the effect of L-NNA on RSNA in SAD rats.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Physiology, Hebei Medical College, Shijiazhuang.
authors.forename: J L
authors.initials: JL
authors.lastname: Liu
authors.forename: W Y
authors.initials: WY
authors.lastname: Zhang
authors.forename: S Y
authors.initials: SY
authors.lastname: Ho
mesh_terms: D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007668:Kidney / Q000294:innervation*; D008297:Male; D019335:Nitroarginine; D051381:Rats; D017207:Rats, Sprague-Dawley; D013564:Sympathetic Nervous System / Q000187:drug effects*
chemical_list: D019335:Nitroarginine; D001120:Arginine