Sx. Ma et al., EFFECTS OF L-ARGININE-DERIVED NITRIC-OXIDE SYNTHESIS ON NEURONAL-ACTIVITY IN NUCLEUS-TRACTUS-SOLITARIUS, American journal of physiology. Regulatory, integrative and comparative physiology, 37(2), 1995, pp. 487-491
The purpose of these studies was to determine the effects of L-arginin
e-derived nitric oxide (NO) synthesis on neuronal activity in solitary
tract nucleus (NTS) neurons. Single unit activity was recorded extrac
ellularly from medial NTS neurons in Fischer-344 rats in vivo and in v
itro. In anesthetized rats with arterial pressure maintained constant,
N-G-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg iv), an inhibitor
of NO synthesis, decreased the discharge rate in 12 of 14 neurons and
increased the discharge rate in two. After injection of L-NAME, the s
lowing of neuronal activity began within 2-5 min, and maximal response
s were observed 12-15 min after injection. The decreases in activity w
ere reversed within 12-15 min with L-arginine (30 mg/kg iv) or immedia
tely with nitroglycerin (NTG, 10-30 mu g/kg iv). In superfused rat bra
in slices, the discharge rate was reduced by 1 mM L-NAME in seven neur
ons, increased in two, and unchanged in one. The decreases in discharg
e rate were reversed by 2 mM L-arginine (4 of 6 neurons) and by 10-30
mu M NTG (6 of 7 neurons). The results show that L-arginine-derived NO
can affect the spontaneous discharge rate of NTS neurons. We conclude
that NO may influence the excitability of NTS neurons involved in cen
tral autonomic control.