Circulation research
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Circulation research · Oct 1995
L-arginine-induced conducted signals alter upstream arteriolar responsivity to L-arginine.
Our purpose was to determine whether L-arginine was involved in vascular communication between downstream and upstream locations within a defined microvascular region. Arteriolar diameter was measured for the branches along a transverse arteriole in the superfused cremaster of anesthetized (pentobarbital sodium, 70 mg/kg i.p.) hamsters (N = 53). The upstream branch arterioles dilated significantly to locally applied L-arginine (100 mumol/L pipette concentration) only if the downstream branches (approximately 1400 microns away) were preexposed. ⋯ Downstream-applied L-arginine also induced a conducted vasodilation (+17.8 +/- 2.8%; n = 14) 1327 +/- 166 microns upstream. This response was completely blocked by simultaneous sucrose (600 mOsm), halothane (0.0345%), or N omega-nitro-L-arginine (L-NNA, 100 mumol/L) exposure to the feed vessel (second micropipette) midway between the downstream site of L-arginine exposure and the upstream observation site. An acetylcholine-induced conducted vasodilation (+18.1 +/- 2.6%, n = 8) was also completely blocked by sucrose, halothane, or L-NNA.(ABSTRACT TRUNCATED AT 250 WORDS)