Regional brain activation by bicuculline visualized by functional magnetic resonance imaging. Time-resolved assessment of bicuculline-induced changes in local cerebral blood volume using an intravascular contrast agent

GABAergic effect on resting-state functional connectivity: Dynamics under pharmacological antagonism

“…This results in decreased GABA binding at the terminals of inhibitory neurons and hence decreased inhibitory activity, which further leads to increased neural activity (Glass et al, 1980). Under the effect of bicuculline, we observe a significant increase in the SEP response and the somatosensory BOLD activation induced by electrical forepaw stimulation, consistent with previous work (Reese et al, 2000;Tsurugizawa et al, 2010). Interestingly, not only the amplitude of BOLD response but also the spatial extent of the activation was enhanced, which expanded to subcortical areas and posterior cortical regions such as the visual cortex.…”

“…Using the AUC map, it can be seen that BIC increased CBF highly in the Thal and CPu while slightly less in SI, SII and lowest in Hipp (Fig. 7b), reflecting the trend of GABA A receptor distribution as consistent with previous study (Reese et al, 2000). The timecourses of CBF changes under bicuculline and vehicle are shown in Fig.…”

“…CBF has been shown to increase by seven folds after administration of 1.2mg/kg of bicuculline (Meldrum and Nilsson, 1976) where the GABA A receptor in particular has been suggested to be a key regulator (Chi et al, 2011;Kocharyan et al, 2007). Similarly, more than 60% increase of CBV was reported by infusing bicuculline up to 1.5mg/kg (Mueggler et al, 2001;Reese et al, 2000). In this study, a very low dose of bicuculline (0.06mg/kg/h) was slowly infused.…”

Differential Recovery of Multimodal MRI and Behavior after Transient Focal Cerebral Ischemia in Rats

“…sion/diffusion declines but remained abnormal far longer. These findings are in accord with previous animal studies reporting loss of stimulus-evoked cerebral hemodynamic responses that slowly recovered but were still significantly depressed up to 24 h after full renormalization of ADC (Reese et al, 2000;Schmitz et al, 1997). They are also supported by a human study showing persistently dysfunctional metabolic activity within the affected hemisphere of patients with clinically diagnosed transient ischemic attack (TIA) subsequently lacking ischemic lesions or hypoperfusion (Bisschops et al, 2002).…”

Relative Changes in Cerebral Blood Flow and Neuronal Activity in Local Microdomains during Generalized Seizures

“…However, as shown in the figure, large CBF increases were often present even when systemic blood pressure was at or below baseline, so that the increases in CBF cannot be explained entirely by blood pressure changes. This finding agrees with previous studies showing cerebral autoregulation independent of changes in systemic blood pressure (Hernandez et al, 1978;Reese et al, 2000). To clarify this further, we analyzed CBF changes separately for the 3 out of 14 tonic-clonic seizures in which the systemic blood pressure increased by less than 15% or decreased during seizures.…”