Showing papers by "Costantino Iadecola published in 1990"
TL;DR: The slow temporal profile of the cerebrovasodilation is compatible with the hypothesis that in cerebral cortex local neurons mediate the vasodilation by interstitial release of vasoactive agents rather than by a direct action of neural processes on blood vessels.
Abstract: Laser–Doppler flowmetry was used to continuously monitor cortical CBF during electrical stimulation of the fastigial nucleus (FN). Rats were anesthetized with isoflurane (0.75–5%), paralyzed, and artificially ventilated. The LDF probe was placed over a target region of the parietal cortex through a burr hole. The hypertension associated with FN stimulation was prevented by spinal cord transection at C1 with arterial pressure maintained by i.v. infusion of phenylephrine. After cord transection, CBF changed linearly with changes in arterial pco2 (r = 0.93; n = 23). FN stimulation (50–100 μA, 50 Hz, 1 s on/1 s off) produced sustained increases in CBF that developed slowly, reaching 50% of maximum within 24 ± 1 s of stimulation (n = 17). After stimulation, CBF returned to baseline gradually within a time period (84–540 s) proportional to the duration of the stimulation (r = 0.93; n = 15). The CBF response was stimulus frequency and intensity dependent, was elicited only from restricted sites in FN, and was ab...
73 citations
TL;DR: The FPR results from excitation and the FDR inhibition of reticulospinal sympathoexcitatory axons of RVL; the FPR is a consequence of excitation of axons arising from neurons in an as yet unidentified area of lower brainstem projecting to or through the FN and with collateral branches innervating RVL mono- or polysynaptically.
38 citations
TL;DR: The results indicate that the cerebrovascular and cardiovascular responses elicited from the FN are functionally distinct and provide additional evidence for the notion that these responses are mediated by different neural pathways and transmitters.
Abstract: We studied the effects of chloralose anesthesia on the elevation in arterial pressure (AP), heart rate (HR), and regional CBF (rCBF) elicited by stimulation of the cerebellar fastigial nucleus (FN). Rats were anesthetized with an initial dose of chloralose (40 mg/kg s.c.), paralyzed, and artificially ventilated. The FN was stimulated (50-100 microA, 50 Hz, 1 s on/1 s off) with microelectrodes stereotaxically implanted. During the stimulation AP was carefully maintained within cerebrovascular autoregulation. CBF was measured by the [14C]iodoantipyrine technique with regional dissection. In rats that received only the initial dose of chloralose, FN stimulation elevated rCBF in brain and spinal cord, up to 209 +/- 13% of control in frontal cortex (n = 5; p less than 0.01, analysis of variance). Administration of additional chloralose (10 mg/kg i.v., 30 min prior to measurement of CBF) did not affect resting rCBF (n = 5), the EEG, or the elevation in AP and HR elicited by FN stimulation (n = 4). However, the additional chloralose abolished the elevations in rCBF (n = 5; p greater than 0.05). Thus, the cerebrovasodilation elicited from the FN is more susceptible to the effects of additional anesthesia than the elevation in AP and HR. These results indicate that the cerebrovascular and cardiovascular responses elicited from the FN are functionally distinct and provide additional evidence for the notion that these responses are mediated by different neural pathways and transmitters.
19 citations
TL;DR: In this article, the authors examined whether epinephrine contributes to the increase in regional cerebral blood flow (rCBF) evoked by electrical stimulation of the dorsal medullary reticular formation (DMRF).
11 citations
TL;DR: It is concluded that non-neuronal cells, most likely activated macrophages, may be an important factor regulating local cerebral perfusion, after acute neuronal death.
10 citations