Lindauer U, Megow D, Schultze J, Weber J R, Dirnagl U
Department of Neurology, Humboldt University, Berlin, Germany.
Neurosci Lett. 1996 Oct 4;216(3):207-10. doi: 10.1016/0304-3940(96)13044-5.
Nitric oxide synthase (NOS) inhibition reduces the regional cerebral blood flow (rCBF) responses to somatosensory stimulation. It is controversial whether this is caused by a signalling role of nitric oxide (NO) between neurons and vascular smooth muscle, or by effects of NOS inhibition on neuronal activity. We here report that more than 85% inhibition of NOS activity by topical application of the NOS inhibitor N omega-nitro-L-arginine (L-NNA) for 2 h does not affect somatosensory evoked potentials (SEPs) elicited by vibrissal deflection or electrical forepaw stimulation in choloralose anaesthetised rats equipped with a closed cranial window, whereas cerebral blood flow (CBF) responses due to these stimulation paradigms are reduced by approximately 60%. We conclude that the decrease of the regional vascular response to increased neuronal activity during NOS inhibition is not caused by a suppression of neuronal activity.
