The levels of noradrenaline, neuropeptide Y, 5-hydroxytryptamine, and substance P were measured and compared between the large arteries of the circle of Willis and the small cerebral vessels of the pia mater in the rat, rabbit, cat, and monkey. In all species, noradrenaline and neuropeptide Y concentrations were greater in the larger arteries than in small pial vessels. Noradrenaline concentrations were dramatically reduced following cervical sympathectomy, with the extent of diminution differing greatly in the various species; the effects of cervical ganglionectomy on neuropeptide Y concentrations were less pronounced. 5-Hydroxytryptamine concentrations in rats, cats, and rabbits were significantly greater in the small pial vessels, although measurable concentrations existed in the circle of Willis. In cats and monkeys, substance P was found in major arteries, but was not detectable at the level of the small pial vessels. The differences in the regional distribution of the various neurotransmitter candidates in the cerebrovascular bed may reflect their physiological significance.
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http://dx.doi.org/10.1038/jcbfm.1987.93 | DOI Listing |
Over the past two decades, rapid advancements in magnetic resonance technology have significantly enhanced the imaging resolution of functional Magnetic Resonance Imaging (fMRI), far surpassing its initial capabilities. Beyond mapping brain functional architecture at unprecedented scales, high-spatial-resolution acquisitions have also inspired and enabled several novel analytical strategies that can potentially improve the sensitivity and neuronal specificity of fMRI. With small voxels, one can sample from different levels of the vascular hierarchy within the cerebral cortex and resolve the temporal progression of hemodynamic changes from parenchymal to pial vessels.
View Article and Find Full Text PDFMed Image Anal
November 2024
Department of Electrical and Electronic Engineering, College of Engineering, Yonsei University, Seoul, Republic of Korea. Electronic address:
Cerebral Microbleeds (CMBs) are chronic deposits of small blood products in the brain tissues, which have explicit relation to various cerebrovascular diseases depending on their anatomical location, including cognitive decline, intracerebral hemorrhage, and cerebral infarction. However, manual detection of CMBs is a time consuming and error-prone process because of their sparse and tiny structural properties. The detection of CMBs is commonly affected by the presence of many CMB mimics that cause a high false-positive rate (FPR), such as calcifications and pial vessels.
View Article and Find Full Text PDFJ Chin Med Assoc
November 2024
Department of Radiology, Taipei Veterans General Hospital and National Yang Ming Chiao Tung University School of Medicine, Taipei, Taiwan, ROC.
Background: Transvenous coil embolization (TVCE) is a common and effective treatment for cavernous sinus dural arteriovenous fistulas (CSDAVFs). However, some patients may experience residual fistulas or worsening visual symptoms after the procedure. This study aimed to compare the effectiveness of transvenous coil and Onyx embolization (TVCOE) with TVCE in treating CSDAVFs.
View Article and Find Full Text PDFJ Clin Med
October 2024
Department of Medicine and Surgery, University of Parma, 43121 Parma, Italy.
Reversible cerebral vasoconstriction syndrome (RCVS) is a rare but significant cause of intracranial arteriopathy and stroke in young adults. The syndrome encompasses a spectrum of disorders radiologically characterized by reversible narrowing and dilation of intracranial arteries, often triggered by vasoactive drugs or the postpartum period. The hallmark clinical feature of RCVS is thunderclap headache with or without other neurological signs.
View Article and Find Full Text PDFNeuroradiology
October 2024
Department of Neurosurgery, National Hospital Organization, Osaka National Hospital, 2-1-14 Hoenzaka, Chuo-ku, Osaka, 540-0006, Japan.
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