scholarly journals Effect of Apomorphine on the Relationship between Local Cerebral Glucose Utilization and Local Cerebral Blood Flow (with an Appendix on its Statistical Analysis)

1982 ◽  
Vol 2 (4) ◽  
pp. 487-499 ◽  
Author(s):  
James McCulloch ◽  
Paul A. T. Kelly ◽  
Ian Ford

The alterations in local glucose utilization and local blood flow in 36 discrete regions of the central nervous system (CNS) that occur following the intravenous administration of the putative dopaminergic agonist, apomorphine (0.5 mg/kg), have been measured using the quantitative autoradiographic 14C-2-deoxyglucose and 14C-iodoantipyrine techniques. In eight of the regions examined (frontal and sensory-motor cortices, ventral thalamus, caudate nucleus, globus pallidus, substantia nigra, subthalamic nucleus, and posterior cerebellar hemisphere), significant elevations of local cerebral blood flow (CBF) were observed following apomorphine administration. In these eight regions, proportionately similar, significant elevations in local glucose utilization were observed following apomorphine. In two of the regions investigated (anterior cingulate cortex and lateral habenular nucleus), significant reductions in both local blood flow and glucose utilization were observed following apomorphine administration. In the majority of regions examined (26 of the total 36), apomorphine did not alter significantly either blood flow or glucose use. Using a statistical approach, described in detail in an appendix, the relationship between local rates of glucose utilization and local levels of tissue blood flow was analyzed. A relationship between local CBF and local glucose utilization was found following apomorphine, and the nature of this relationship was indistinguishable from that observed in control animals. In no region of the CNS was a significant deviation from the normal CBF–glucose use relationship demonstrated following apomorphine administration. These results point to the greater importance of the effects of apomorphine upon tissue metabolic activity, rather than its direct vascular action, as being the major mechanism underlying the observed alterations in local CBF. The statistical methods provide a rigorous analytical approach to the analysis of alterations in the relationship, both locally and globally, of blood supply to glucose utilization.

1985 ◽  
Vol 5 (1) ◽  
pp. 58-64 ◽  
Author(s):  
W. Kuschinsky ◽  
S. Suda ◽  
L. Sokoloff

The relationship between local cerebral glucose utilization (LCGU) and local CBF (LCBF) was examined during the action of γ-hydroxybutyrate (GHB) (900 mg/kg i.v.) in conscious rats. GHB induced discrepant effects on blood flow and metabolism. LCGU was markedly depressed in all structures examined, whereas LCBF was differently affected in that no related changes were observed. Global glucose utilization was markedly depressed (- 51%), whereas global blood flow was not significantly altered. The marked dissociation between the changes in global glucose utilization and global blood flow induced by GHB is reflected only to a minor degree in the local values inasmuch as the correlation between LCGU and LCBF was only slightly weakened and its heterogeneity was increased.


1992 ◽  
Vol 15 ◽  
pp. 258B
Author(s):  
K. Satoh ◽  
M. Narita ◽  
T. Someya ◽  
S. Takahashi ◽  
T. Suzuki ◽  
...  

1988 ◽  
Vol 254 (2) ◽  
pp. H250-H257
Author(s):  
H. Schrock ◽  
W. Kuschinsky

Rats were kept on a low-K+ diet for 25 or 70 days. Local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were measured in 31 different structures of the brain by means of the [14C]iodoantipyrine and [14C]2-deoxy-D-glucose method. After 25 and 70 days of K+ depletion LCBF was decreased significantly in 27 and 30 structures, respectively, the average decrease being 19 and 25%. In contrast, average LCGU was not changed. Cisternal cerebrospinal fluid (CSF) K+ concentration decreased significantly from 2.65 +/- 0.02 mM in controls to 2.55 +/- 0.02 mM and 2.47 +/- 0.02 mM in the two treated groups (P less than 0.01). CSF [HCO3-], pH, and PCO2 were increased in K+-depleted animals. These data show that K+ depletion induces an increase in CSF pH and a decrease in CSF K+ concentration, both of which cause a reduction in cerebral blood flow. The increased CSF PCO2 is secondary to the reduction of blood flow, since brain metabolism and arterial PCO2 remained constant.


1993 ◽  
Vol 265 (4) ◽  
pp. H1243-H1248 ◽  
Author(s):  
K. Waschke ◽  
H. Schrock ◽  
D. M. Albrecht ◽  
K. van Ackern ◽  
W. Kuschinsky

The effects of a blood exchange on cerebral blood flow and glucose utilization were studied. A near to total blood exchange (hematocrit < 3%) was achieved in conscious rats by isovolemic hemodilution. Ultrapurified, polymerized, bovine hemoglobin (UPBHB) served as a blood substitute. Local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU) were measured in 34 brain structures of conscious rats by means of the ido[14C]antipyrine and the 2-[14C]-deoxy-D-glucose methods. A group of rats without blood exchange served as control. After blood exchange LCBF increased from 36 to 126% in the different brain structures resulting in a nearly doubled mean cerebral blood flow (+82%). LCGU increased only moderately by 0-24%. Significant increases in LCGU were observed in 16 brain structures. Mean cerebral glucose utilization slightly increased (+14%). The relationship between LCGU and LCBF was found to be tight both in the control group (r = 0.95) as well as after blood replacement (r = 0.94), although it was reset to a higher overall LCBF-to-LCGU ratio. The profound increases in LCBF observed after blood exchange, which were not paralleled by comparable increases in LCGU, might be explained by a reduction of blood viscosity after blood exchange. Additional effects of blood exchange observed in the present study were an increase of mean arterial blood pressure and a decline of heart rate. The results indicate that replacement of blood with the hemoglobin-based oxygen carrier UPBHB appears to meet the cerebral circulatory and metabolic demands of the brain tissue.


1986 ◽  
Vol 251 (6) ◽  
pp. H1333-H1340 ◽  
Author(s):  
B. Klein ◽  
W. Kuschinsky ◽  
H. Schrock ◽  
F. Vetterlein

Previous investigations have established a strong correlation between local cerebral blood flow (LCBF) and local cerebral glucose utilization (LCGU). In the present study the relationship between density of perfused brain capillaries and LCBF or LCGU was investigated in conscious and anesthetized rats. Perfused capillaries were stained by labeling the plasma with the gamma globulin-coupled fluorochromes, fluorescein isothiocyanate (FITC) and lissamine-rhodamine B 200 (RB 200). The density of perfused capillaries was determined in 12 different brain structures by fluorescence microscopy of embedded brain sections following coronal sectioning in a cryostat. Significant differences were found among brain structures investigated; the lowest density of perfused capillaries was found in the white matter (e.g., corpus callosum 162 fragments/mm2), whereas the highest values were determined in the structures of the auditory system (e.g., inferior colliculus 810 fragments/mm2). LCBF and LCGU were measured in two separate groups of rats using standard autoradiographic methods. In all three experimental groups, the same structures were identified and measured with a high degree of accuracy and local resolution. Density of perfused capillaries correlated well with LCBF (r = 0.93) and even better with LCGU (r = 0.97). In addition to the relationship between LCGU and LCBF established by earlier studies, these data show the intimate interrelationship between LCGU, density of perfused capillaries, and LCBF.


2001 ◽  
Vol 11 (4) ◽  
pp. 510-519
Author(s):  
Weizhao Zhao ◽  
Ofelia F. Alonso ◽  
Judith Y. Loor ◽  
Raul Busto ◽  
Myron D. Ginsberg

Object Using autoradiographic image averaging, the authors recently described prominent foci of marked glucose metabolism-greater-than-blood-flow uncoupling in the acutely traumatized rat brain. Because hypothermia is known to ameliorate injury in this and other injury models, the authors designed the present study to assess the effects of post-traumatic therapeutic hypothermia on the local cerebral metabolic rate of glucose (LCMRglu) and local cerebral blood flow (LCBF) following moderate parasagittal fluid-percussion head injury (FPI) in rats. Methods Either cranial hypothermia (30°C) or normothermia (37°C) was induced for 3 hours in matched groups of rats immediately after FPI; LCMRglu and LCBF were assessed 3 hours after concluding these temperature manipulations. In rats subjected to FPI, regardless of whether normothermia or hypothermia ensued, LCBF was reduced relative to the sham-injury groups. In addition, when FPI was followed by hypothermia (FPI–30°C group), the subsequent LCBF was significantly lower (35–38% on average) than in FPI–37°C rats. Statistical mapping of LCBF difference imaging data revealed confluent cortical and subcortical zones of significantly reduced LCBF (largely ipsilateral to the prior injury) in FPI–30°C rats relative to the FPI–37°C group. Local glucose utilization was reduced in both hemispheres of FPI–37°C rats relative to the sham-injury group and was lower in the right (traumatized) hemisphere than in the left. However, LCMRglu values were largely unaffected by temperature manipulation in either the FPI or sham-injury groups. The LCMRglu/LCBF ratio was nearly doubled in FPI–30°C rats relative to the FPI–37°C group, in a diffuse and bihemispheric fashion. Linear regression analysis comparing LCMRglu and LCBF revealed that the FPI–37°C and FPI–30°C data sets were completely nonoverlapping, whereas the two sham-injury data sets were intermixed. Conclusions Despite its proven neuroprotective efficacy, early posttraumatic hypothermia (30°C for 3 hours) nonetheless induces a moderate decline in cerebral perfusion without the (anticipated) improvement in cerebral glucose utilization, so that a state of mild metabolism-greater-than-blood-flow dissociation is perpetuated.


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