Cerebral relative regional

Indicator-dilution theory (Axel 1980 Rosen et al. 1989) leads to the formula for calculation of the relative regional cerebral blood volume (rrCBV)... 

Relatively few human imaging studies have evaluated the effects of marijuana or THC on metabolism or blood flow. Acute intravenous THC in both normal controls and habitual marijuana users led to increased an increased regional cerebral metabolic rate (CMR) in the cerebellum. This increase is positively correlated both with concentrations of THC in the plasma and with the intensity of the subjective sense of intoxication [5]. In a 1997 PET/[lsO]water study with 32 abusers [6], THC dose-depend-ently increased cerebral blood flow (CBF) in the frontal regions, insula... 

Although liver uptake of this compound is relatively high, the ischemic regions of the heart were visualized. SPECT images obtained from cats that were administered BMS-181321 one hour after middle cerebral artery occlusion (MCAO) showed selective brain retention in the ischemic territory of the MCA... 

Li+ was first found to interfere with inositol lipid metabolism when significantly decreased levels of myo-inositol were observed in the cerebral cortex of Li+-treated rats [89]. Subsequent work revealed a corresponding increase in the levels of Ins( 1 )P [90] and this behavior was shown to be the result of a Li+-induced inhibition of IMPase, the enzyme which dephosphorylates the monophosphates Ins(l)P, Ins(3)P, and Ins(4)P to produce free inositol [91]. These results stimulated much research in this field involving a wide variety of cell types, tissues, and animals where the Li+ inhibition of IMPase was found to be ubiquitous. However, it was found that, in vivo, this Li+-induced effect is predominantly limited to the brain, being observed in different regions of the brain to different extents, with similar results for both acute and chronic treatment with Li+. It is probable that those cells that are able to accumulate inositol, or which are exposed to and can rapidly import an extracellular supply of inositol, may be relatively insensitive to the effects of Li+. 

The nigrostriatal pathway participates in the production of smooth physical motion. It is not the brain area that works to initiate movement, which is in the cerebral cortex (pyramidal tract) it is the region that helps one to have fluid motion (extrapyramidal tract). Although many neurotransmitters are found in this latter system, two neurotransmitters—dopamine and acetylcholine—are predominantly involved in this pathway. The brain normally maintains a relatively stable ratio of dopamine and acetylcholine in the pathway. However, when something happens to upset this ratio, problems arise. 

Abnormal recruitment of the hippocampus during memory retrieval in schizophrenia. The right hippocampal region indicated in red in (a) showed increased relative cerebral blood flow (rCBF) during high accuracy recall when compared with both lexical retrieval at baseline and low accuracy recall in healthy control subjects ("controls" in (b)). This normal pattern was absent in the schizophrenia group and all three recall conditions were associated with higher rCBF in the hippocampus ("schizophrenics" in (b))... 

Cyclic AMP has been implicated in synaptic transmission due to its actions on a number of important synaptic and neuronal events, such as membrane permeability, synaptic membrane phosphorylation, neurotransmitter synthesis, and cell growth and differentiation. As pointed out earlier, neurotransmitter-receptor interactions can result in direct physical perturbations of the membrane with consequent alterations in membrane permeability to specific ions. This effect is particularly the case when the ionophore is located near the receptor. However, if the ionic channel is distant from the receptor, mechanisms such as phosphorylation can result in an alteration of channel permeability. Cyclic AMP is known to lead to a hyperpolarization of neurons in a number of brain regions such as the cerebral cortex, the caudate nucleus, the peripheral paravertebral sympathetic ganglia, the cerebellar cortex, and the hippocampus. Although it has been hypothesized that this hyperpolarization is the consequence of the phosphorylation of specific neuronal membrane proteins, the relatively short duration of hyperpolarization... 

---