Innervation of the human middle meningeal artery: immunohistochemistry, ultrastructure, and role of endothelium for vasomotility.

The majority of nerve fibers in the middle meningeal artery and branching arterioles are sympathetic, storing norepinephrine and neuropeptide Y (NPY). A sparse supply of fibers contain acetylcholinesterase activity and immunoreactivity toward vasoactive intestinal peptide (VIP), peptidine histidine methionine (PHM), and calcitonin gene-related peptide (CGRP). Only few substance P and neuropeptide K immunoreactive fibers are noted. Electronmicroscopy shows axons and terminals at the adventitial medial border of the human middle meningeal artery, with a fairly large distance to the smooth muscle cells (>500 nM). Several axon profiles contain vesicles of different types, including putative sensory profiles. The perivascularly stored signal substances, norepinephrine and NPY induced vasoconstrictor. Relaxations were induced by acetylcholine and substance P, and these were significantly reduced in arteries without endothelium, while the responses to norepinephrine, NPY, VIP, PHM, and CGRP were not changed by endothelium removal. Blockade experiments showed that the vasomotor responses to norepinephrine were blocked by prazosin, to NPY by BIBP 3226, acetylcholine by atropin, substance P by RP 67580, and the human alpha-CGRP response by human alpha-CGRP(8-37).

The sphenoparietal sinus of breschet: does it exist? An anatomic study.

BACKGROUND AND PURPOSE: The termination of the superficial middle cerebral vein is classically assimilated to the sphenoid portion of the sphenoparietal sinus. This notion has, however, been challenged in a sometimes confusing literature. The purpose of the present study was to evaluate the actual anatomic relationship existing between the sphenoparietal sinus and the superficial middle cerebral vein. METHODS: The cranial venous system of 15 nonfixed human specimens was evaluated by the corrosion cast technique (12 cases) and by classic anatomic dissection (three cases). Angiographic correlation was provided by use of the digital subtraction technique. RESULTS: The parietal portion of the sphenoparietal sinus was found to correspond to the parietal portion of the anterior branch of the middle meningeal veins. The sphenoid portion of the sphenoparietal sinus was found to be an independent venous sinus coursing under the lesser sphenoid wing, the sinus of the lesser sphenoid wing, which was connected medially to the cavernous sinus and laterally to the anterior middle meningeal veins. The superficial middle cerebral vein drained into a paracavernous sinus, a laterocavernous sinus, or a cavernous sinus but was never connected to the sphenoparietal sinus. All these venous structures were demonstrated angiographically. CONCLUSION: The sphenoparietal sinus corresponds to the artificial combination of two venous structures, the parietal portion of the anterior branch of the middle meningeal veins and a dural channel located under the lesser sphenoid wing, the sinus of the lesser sphenoid wing. The classic notion that the superficial middle cerebral vein drains into or is partially equivalent to the sphenoparietal sinus is erroneous. Our study showed these structures to be independent of each other; we found no instance in which the superficial middle cerebral vein was connected to the anterior branch of the middle meningeal veins or the sinus of the lesser sphenoid wing. The clinical implications of these anatomic findings are discussed in relation to dural arteriovenous fistulas in the region of the lesser sphenoid wing.

Morphological picture in paroxysmal nocturnal hemoglobinuria. Case report.

25-year-old woman with paroxysmal nocturnal hemoglobinuria was admitted to the hospital because of headache, progressing right hemiparesis and speech disorders. Several days later patient lost consciousness. Cerebrospinal fluid was xanthochromic with increased pleocytosis and protein level. CT-scan revealed ischemic area with hemorrhagic focus within left cerebral hemisphere. Patient died 3 weeks after the admission. Brain section revealed hemorrhagic infarct in the cortex of the left parietal lobe, thrombosis of the superior sagittal sinus and "respiratory brain" changes. Microscopic examination revealed meningeal venous thrombosis, hemorrhagic infarct, vasculitis, abundant accumulation of bacteria within blood vessels, and other pathological changes such as petechiae, perivascular exudates and small, round areas composed of acellular fibrillary network. There were no macrophages and GFAP-positive astrocytes in any of these areas. Authors suggest that weak cell reactivity may be connected with alterations in cell membranes, mainly low phosphatidylinositol (GPI) content.

The vascular supply of the endolymphatic sac.

The vascular anatomy of the endolymphatic sac in guinea pigs was examined following intravascular injection of silicone rubber (Microfil). Methacrylate resin of low viscosity (Mercox) was used to obtain vascular corrosion casts for scanning electron microscopy, which allowed more accurate differentiation between arteries and veins. The extensive vascular system around the sac comprises both arteries and veins, as well as lymphatic vessels. The arterial supply is derived mainly from the posterior meningeal artery in the posterior cranial fossa. In some cases a small artery also leads to the sac from the posterior vestibular artery in the labyrinth (in 7 of the 35 animals investigated). It courses together with the vein of the vestibular aqueduct along the walls of the endolymphatic duct. The blood is drained over the intermediate portion of the endolymphatic sac, which becomes lodged in a rich meshwork of capillaries, venules, veins and a few small arteries. A few venous trunks from both sac walls fuse with the vein of the vestibular aqueduct, which drains blood from the vestibule to the sigmoid sinus. Scanning electron microscopy also revealed numerous anastomosing vessels within bone channels with adjacent bone marrow sinusoids, which also probably contribute to the vascular supply of the endolymphatic sac.

Gross and histologic study of the rostral epidural rete mirabile and the cavernous sinus in one-humped camels.

Gross and histologic features of the rostral epidural rete mirabile (carotid rete) and the cavernous sinus in one-humped camels were studied. It was evident that the branches of the carotid rete share a common tunica adventitia with the veins of the cavernous sinus. Transmission electron microscopy of the rostral epidural rete mirabile and the cavernous sinus revealed gap junctions in endothelial cells lining the walls of the arterial rete branches and veins. The internal elastic lamina of rete branches were fenestrated. Some of these structural features could facilitate countercurrent heat exchange between the rete branches and the venous plexus of the cavernous sinus to regulate brain temperature.

[Cerebral thrombosis in paroxysmal nocturnal hemoglobinuria: case report]. / Przypadek zakrzepicy naczyn mózgowych w przebiegu nocnej napadowej hemoglobinurii.

Clinical, radiological and postmortem findings in a 25-year old woman with paroxysmal nocturnal hemoglobinuria (PNH) who developed cerebral thrombosis are presented. The pathogenesis of the PNH is discussed.

[Hyperplasia of the adrenergic nerve fibers of the vessels and myocardium in rats with spontaneous hypertension]. / Giperplaziia adrenergicheskikh nervnykh volokon v sosudakh i miokardee u krys so spontannoi gipertenziei.

Adrenergic innervation of the myocardium vessels was morphometrically studied in 4-, 8-, 12- and 20-week-old spontaneously hypertensive rats (SHR). The increase of cardiac adrenergic nerves was found in the early period of persistent hypertension (in 12-week-old SHR). In the vessels this increase was more pronounced and started earlier, at prehypertensive stage (in 4-week-old SHR). The data obtained confirm the hyperplasia of the terminal part of the sympathetic nervous system, this reflecting the increased sympathetic influence on cardiovascular system in hypertension.

[The submucosal structure of the endolymphatic sac of guinea pigs].

OBJECTIVE: To investigating the submucosal structure of the endolymphatic sac (ES), so as to analyse the role of ES in the function of inner ear. METHOD: The temporal bone of the guinea pigs were cleared in methyl salicylate and inspected under a stereomicroscope. The ultrastructure of endolymphatic sac has been observed by transmission electron microscope. RESULT: The extensive vascular system around the sac and has compact contact with sinus sigmoid. Its submucosal space comprises both arterioles and venules, as well as lymphatic sinus. CONCLUSION: The result suggests that the ES is a very metabolically active structure and has a pressure regulating function. The disturbance of endolymphatic resorptive function seems to result endolymphatic hydrops after the vascular supply poverty of endolymphtic sac. It's may be the causative factor of Meniere's disease.

Microvasculature of the human cerebral meninges.

In the present study, the human cerebral meninges were rich in blood vessels, but no capillaries were noted. The meningeal arteries ran over the veins where they crossed. Several arterial anastomoses existed on the cortical surface. The meningeal arteries were classified into four parts; the conducting artery approximately 700 microm in diameter, distributing artery approximately 200 microm in diameter, precortical artery approximately 60 microm in diameter and cortical artery approximately 30-40 microm in diameter. A single distributing artery supplied the area of approximately 3.5 x 2.0 mm on the brain surface. They further ramified into precortical arteries which stemmed cortical arteries. These precortical arteries had the distributing area of 1 mm2 and this distributing area was the same size as the width of human ocular dominant column of the visual cortex. Constriction, like a sphincter, was observed at the bifurcation of the distributing arteries. The cerebral blood vessels, which regulated the blood flow and reacted to autonomic nerve stimuli, seemed to correspond to the distributing arteries.

The fenestrated blood vessels of the endolymphatic sac. A freeze-fracture and transmission electron microscopic study.

The fenestrated blood vessels surrounding the endolymphatic sac in guinea pigs were investigated with the help of freeze-fracturing. The technique exposes the structure and distribution of vascular pores as well as interendothelial bridges or tight junctions between vascular endothelial cells. It is possible to get a three-dimensional comprehension of the vascular structure which can be compared with that of conventional transmission electron microscopy (TEM). Discontinuity in the junctional elements as seen in some endothelial layers and the high number of fenestrations organized in geometric patterns, as well as the abundant, randomly distributed micropinocytotic vesicles seem to bear out the theory that the endolymphatic sac is one of the most metabolically active parts of the inner ear and may be involved in the turnover of endolymph.

A histological, ultrastructural and immunohistochemical study of superficial temporal arteries and middle meningeal arteries in moyamoya disease.

Pathologic changes in superficial temporal arteries (STA) and middle meningeal arteries (MMA) biopsied from 15 patients with moyamoya disease (MD) who had undergone cerebro-temporal arterio-synangiosis were studied histologically, ultrastructurally and immunohistochemically. The main pathologic features were: proliferation of smooth muscle cells (SMCs) and thickening of the intima, degeneration and destruction of SMCs in the media and intima, and the presence of condensed organelles in necrosed SMCs or the interstitium among SMCs, or both outside and within the elastica interna (EI). The EI had become thin, porous, fragmented and was even absent in some segments. These changes are different from those of other forms of angiopathy, but identical with those at the ends of internal carotid arteries (ICA) reported by us previously, being pathognomonic for MD. These changes in the STA and MMA reveal that MD involves not only the ICA but also the intra- and extracranial branches of external carotid arteries. The medial necrosis of SMCs seems to be the primary injury of the arterial wall in MD. STA tissue blocks from two cases of MD were stained immunohistochemically. By electron microscopy, IgG-, IgM-, and C3-positive granules were observed on the ER of endothelial and intimal cells. Further studies on more cases are needed to determine whether an immunoreaction has occurred in these arteries.

5-Hydroxytryptamine receptor characterization of human cerebral, middle meningeal and temporal arteries: regional differences.

We have studied the regional distribution of 5-hydroxytryptamine (5-HT) receptor subtypes in fresh circular segments of human cerebral, middle meningeal, and temporal arteries. Vasomotor responses induced by a series of 5-HT agonists and antagonists with some degree of selectivity were studied by using a sensitive in vitro system. Nine 5-HT agonists were examined for contractile effects on the arteries. In cerebral and meningeal arteries 5-carboxamidotryptamine (5-CT) was more potent than 5-HT. The opposite order of potency (5-HT-5-CT) was found in temporal arteries. In the cerebral arteries 5-methoxytryptamine (5-MeOHT) was more potent than sumatriptan while sumatriptan was more potent than 5-MeOHT in meningeal and temporal arteries. The 5-HT1 receptor antagonist, methiothepin, competitively antagonized 5-CT-induced contractions in cerebral arteries, with a pA2 value of 9.05. 5-HT-induced contractions were competitively antagonized by ketanserin (5-HT2) in the temporal arteries pA2 value of 9.06). Methiothepin and ketanserin had non-competitive antagonistic effects in the middle meningeal arteries. The 5-HT3 selective antagonist ondansetron did not cause any shift of the contractions induced by 2-methyl-5-HT in the temporal, cerebral and middle meningeal arteries. These results suggest that the cerebral arteries mainly contain 5-HT1D or 5-HT1-like receptors, and the temporal artery 5-HT2 receptors; the data further indicate the presence of both receptor subtypes in the middle meningeal artery.

Repetitive cortical spreading depression in a gyrencephalic feline brain: inhibition by the novel benzoylamino-benzopyran SB-220453.

Transient cortical depolarization is implicated in the pathology of migraine. SB-220453 is a potent anti-convulsant which inhibits neurogenic inflammation and cortical spreading depression (SD)-evoked nitric oxide release via a novel but unknown mechanism. This study further investigates the effects of SB-220453 on generation and propagation of repetitive SD in the anaesthetized cat. Vehicle or SB-220453 1, 3 or 10 mg/kg was administered intraperitoneally 90 min prior to induction of SD in the suprasylvian gyrus (SG). Changes in d.c. potential were recorded in the SG and the adjacent marginal gyrus (MG). In vehicle-treated animals (n = 7), a brief exposure (6 min) to KCl induced a median (25-75% range) number of five (four to six) and three (two to four) depolarizations over a duration of 55 min (32-59 min) and 51 min (34-58 min) in the SG and MG, respectively. SB-220453 produced dose-related inhibition of the number of events and period of repetitive SD activity. SB-220453 also reduced SD-induced repetitive pial vasodilatation but had no effect on resting haemodynamics. However, when SD events were observed in the presence of SB-220453, it had no effect on metabolic coupling. These results show that SB-220453 produces marked inhibition of repetitive SD in the anaesthetized cat. SB-220453 may therefore have therapeutic potential in treatment of SD-like activity in migraine.