Assessment of peripheral tissue perfusion disorder in streptozotocin-induced diabetic rats using dynamic contrast-enhanced MRI.

Purpose: To assess peripheral tissue perfusion disorder in streptozotocin (STZ)-induced diabetic rats by using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).

Materials And Methods: A rat diabetes model was produced by intravenous injection of STZ. Diabetic rats were sustainably treated with either saline or insulin using an Alzet osmotic pump.

Effect of PK11195 on attenuating the enhancement of glucose utilization induced by quinolinic acid infusion in the rat brain.

PK11195, a selective PBR ligand, has been reported to exert a protective effect against the neuronal damage induced by the intrastriatal infusion of quinolinic acid, an excitatory amino acid. The neuroprotective effect of PK11195 observed at 48 h after the infusion was mediated by the inhibition of microglial activation. The aim of this study is to search the mechanism for the effect of PK11195 other than the inhibition of activation of microglia.

Role of NMDA receptors in the increase of glucose metabolism in the rat brain induced by fluorocitrate.

The effect of inhibition of glial metabolism by infusion of fluorocitrate (FC, 1 nmol/microl, 2 microl) into the right striatum of the rat brain on the glucose metabolism was studied. Significant increases in [(18)F]fluorodeoxyglucose ([(18)F]FDG) uptake (45 min) in the right cerebral cortex and striatum were observed 4h after the infusion of FC, both as determined by the tissue dissection method and autoradiography. No significant increase in the initial uptake of [(18)F]FDG (1 min) was seen in the striatum.

Evaluation of [14C]phenylacetate as a prototype tracer for the measurement of glial metabolism in the rat brain.

[(14)C]Phenylacetate was designed as a prototype tracer for the measurement of glial metabolism, and its potency in comparison with that of [(14)C]acetate was evaluated in this study. Normal rats were intravenously injected with [(14)C]phenylacetate or [(14)C]acetate, and radioactivity concentrations were measured in the plasma, cerebral cortex, cerebellum and peripheral tissues by dissection method. In addition, [(14)C]phenylacetate uptake in the rat brain was compared by autoradiography with that of [(14)C]acetate following the injection of fluorocitrate, a selective glial toxin, into the brain.

Blood flow dependence of the intratumoral distribution of peripheral benzodiazepine receptor binding in intact mouse fibrosarcoma.

The intratumoral distribution of [(11)C]AC-5216 binding, a novel peripheral benzodiazepine receptor (PBR) ligand, was examined by autoradiography both in vitro and in vivo using a murine fibrosarcoma model. The regional distribution of [(11)C]AC-5216 in a tumor in vivo was significantly heterogeneous; the uptake of [(11)C]AC-5216 was comparatively higher in the outer rim of the tumor and was lower in the central area. In contrast, the images obtained following the injection of [(11)C]AC-5216 with a large amount of nonlabeled PK11195 showed a relatively homogeneous distribution, suggesting that [(11)C]AC-5216 uptake represented specific binding to PBRs.

Changes in in vivo [(3)H]-Ro15-4513 binding induced by forced swimming in mice.

Mice were forced to swim for 5 min in water at a temperature of 12 degrees C (cold water swim stress) or 32 degrees C (warm water swim stress), and stress-induced analgesia (SIA) was measured using the tail-flick test. The cold water swim stress induced non-opioid SIA as well as hypothermia, whereas the warm water swim stress caused opioid SIA. The in vivo binding of [(3)H]-Ro15-4513 was measured in the stressed mice and compared with that in control mice.