Characterization of CBF response to somatosensory stimulation: model and influence of anesthetics.
We investigated the cerebral blood flow (CBF) response to somatosensory stimulation. Stimulation of neuronal activity was performed by deflection (2-3/s) of the mystacial vibrissae in rats over a period of 60 s, and regional cortical CBF was measured continuously in the contralateral somatosensory cortex with laser-Doppler flowmetry. CBF within the somatosensory cortex was studied through the parietal bone thinned to translucency (n = 7) or through a closed cranial window with the dura mater removed (n = 7). In addition, the differential effect of anesthetics (halothane-N2O, n = 5; thiobutabarbiturate, n = 5; and alpha-chloralose, n = 7) on the CBF response to stimulation was investigated. After a rapid increase after stimulation onset (maximum reached within 2-3 s), CBF remained above baseline with a slight tendency to decrease despite continued stimulation. On termination of stimulation, CBF fell to near prestimulation values within 2-3 s. The following mean CBF responses above baseline during the 60-s stimulation period were obtained: halothane-N2O anesthesia, 25.4 +/- 5.9%; thiobutabarbiturate anesthesia, 10.6 +/- 2.4%; and alpha-chloralose anesthesia, 16.9 +/- 2.3 (through the translucent bone) and 16.2 +/- 2.9% (closed cranial window, dura removed). We conclude that coupling of CBF to neuronal function has a very high temporal resolution (< 3 s) and that whisker deflection in rats provides a physiological stimulus to study coupling with laser-Doppler flowmetry.
Lindauer
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U
Department of Neurology, Klinikum Grosshadern, Universität München, Germany.
Villringer
A
A
Dirnagl
U
U
D000777:Anesthetics / Q000494:pharmacology*; D000818:Animals; D002540:Cerebral Cortex / Q000098:blood supply* / Q000502:physiology*; D002698:Chloralose / Q000494:pharmacology; D006221:Halothane / Q000494:pharmacology; D007834:Lasers; D008297:Male; D009475:Neurons, Afferent / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D012039:Regional Blood Flow / Q000502:physiology; D013003:Somatosensory Cortex / Q000098:blood supply / Q000502:physiology; D013874:Thiopental / Q000031:analogs & derivatives / Q000494:pharmacology; D014738:Vibrissae / Q000502:physiology
D000777:Anesthetics; D002698:Chloralose; C004316:thiobutabarbital; D013874:Thiopental; D006221:Halothane