The present study will, thus, form the basis for future approaches for the prevention of vascular diseases at age. While the BBB sustains the unique chemical microenvironment critical for neuronal activity in the CNS, it also restricts access to therapeutic drugs. These ECs are distinct from peripheral ECs in that they have a continuous basement membrane with no fenestrae and low pinocytotic activity. Furthermore, complex tight junctions between adjacent ECs further restrict the diffusion of blood-borne substances. It has been estimated that almost all large-molecule drugs and more than 98% of small molecule drugs cannot cross the BBB. Rather, only small lipid-soluble molecules demonstrate significant BBB permeability. Despite recent advances in CNS drug delivering methods, the safe and noninvasive delivery of many potential therapeutics remains a challenge. Indeed, many potential therapies with demonstrated in vitro activity have proven ineffective in vivo due to lack of BBB permeability. It is estimated that neurological disorders constitute at least 6.3% of the global burden and this burden is increasing. However, most of the effective CNS drugs target only three types of disease: affective disorders, chronic pain, and epilepsy. It has been estimated that only 12% of all drugs are active in the CNS, and only 1% are active against diseases other than affective disorders. Furthermore, most traditional CNS drug delivery methods disrupt the BBB in both directions, Loganin resulting in sideeffects and even permanent neural damage. For example, results of trans-cranial CNS drug delivery have been disappointing, and breaching the BBB has been associated with significant adverse events, including edema and leukocyte infiltration. Although some noninvasive and specific approaches have been developed, it may take years before these techniques can be applied clinically in humans. Thus, despite significant advances in our understanding of neurological disease pathogenesis, these disorders will remain a serious global health burden. So, it is of vital importance to find a safe 
and effective way to modulate the Campesterol permeability of BBB to facilitate the entry of therapeutic drugs into the CNS for the treatment of neurological diseases. The vascular endothelial growth factors induce vasculogenesis and angiogenesis during development, wound healing, and tumor growth. Folkman et al and Ide et al found that tumors secrete molecules that promote angiogenesis with increased permeability. In 1989, VEGF was purified, cloned, and shown to be an effective endothelial cell mitogen. Exogenous application of VEGF reduced ischemic damage in an animal model of stroke. However, the effects of VEGF may depend on when it is administered. In addition to neuroprotection mediated by angiogenesis, VEGF can also upregulate expression of the glucose transporter-1, thereby increase glucose transport across the BBB. These studies suggest that VEGF may be used noninvasively to selectively modulate BBB permeability for drug delivery, but VEGF treatment protocols that optimize drug delivery while reducing the risk of hemorrhage must be developed. To this end, we measured BBB permeability following venous injection of different concentrations of VEGF in healthy mice.