AJP - Heart and Circulatory Physiology, Vol 243, Issue 2 226-H235, Copyright © 1982 by American Physiological Society
Global cerebral vasodilation by stimulation of rat fastigial cerebellar nucleus
M. Nakai, C. Iadecola and D. J. Reis
The effects of electrical stimulation of the pressor area of the fastigial
nucleus (FN) of cerebellum on regional cerebral blood flow (CBF) were
examined in anesthetized, paralyzed rats. CBF was measured in tissue
homogenates by the Kety principle using 14C-iodoantipyrine as an indicator
during FN stimulation, during stimulation of the vermal cortex, or after
placement of electrodes in FN (unstimulated controls). Blood gases and
systemic arterial pressures were comparable in the three groups. FN
stimulation elicited a widespread and significant (P less than 0.005)
increase in CBF in 12 of 13 areas. Flow was maximally increased in cerebral
cortex (up to 220% of control) but also rose in selected regions of
telencephalon, diencephalon, mesencephalon, lower brain stem, and in white
matter of the corpus callosum (172%). Flow was not increased in cerebellum.
The increase in CBF persisted after transection of the spinal cord at C1 or
cervical sympathectomy. In five rats, hypercarbia (PCO2 to 63 mmHg)
increased CBF in all 13 regions but in a pattern differing from FN
stimulation. Excitation of neurons originating in, projecting to, or
passing through FN can elicit a potent and virtually global increase of
CBF. The effect appears mediated by intrinsic pathways of the central
nervous system.
