Guimarães F S, de Aguiar J C, Del Bel E A, Ballejo G
Department of Pharmacology, FMRP, Ribeirão Preto, SP, Brazil.
Neuroreport. 1994 Oct 3;5(15):1929-32. doi: 10.1097/00001756-199410000-00022.
Nitric oxide synthase (NOS) accounts for most of the NADPH-diaphorase neuronal activity in the brain. NADPH-diaphorase-positive neurones have been localized at the dorso-lateral part of the periaqueductal grey (PAG), a region related to anxiety. Microinjections of the NOS inhibitors L-NAME (10-200 nmol 0.5 microliter-1) and L-NOARG (10-100 nmol) at this site induced anxiolytic-like effects in the elevated plus maze. These effects, however, occurred only at a limited range of doses and the dose-effect curve had a bell shape, higher doses of both compounds tending to be anxiogenic. The anxiolytic effect of L-NAME was antagonized by a previous microinjection of L-arginine (50 nmol 0.5 microliter-1). These results suggest that NO may play a role in PAG neurotransmission involved in anxiety.
一氧化氮合酶（NOS）占大脑中大部分NADPH-黄递酶神经元活性。NADPH-黄递酶阳性神经元已定位在导水管周围灰质（PAG）的背外侧部分，该区域与焦虑有关。在此部位微量注射NOS抑制剂L-NAME（10 - 200 nmol 0.5微升-1）和L-NOARG（10 - 100 nmol）在高架十字迷宫中诱导出抗焦虑样效应。然而，这些效应仅在有限的剂量范围内出现，且剂量-效应曲线呈钟形，两种化合物的较高剂量往往具有致焦虑作用。L-NAME的抗焦虑作用被预先微量注射L-精氨酸（50 nmol 0.5微升-1）所拮抗。这些结果表明，NO可能在参与焦虑的PAG神经传递中发挥作用。
