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At least 739 records · Page 41Linked to original sources
PubMed2006

Comparison of glass vessels and plastic bags for enclosing living plant parts for headspace analysis.

Plants release volatile chemicals into their surrounding air space that can affect the physiology of neighboring plants and influence the behavior of insects. In studying these interactions, it is desirable to collect volatiles from plants that have not been excised and are growing under as natural conditions as possible. We compared a vessel of borosilicate glass and Nylon-6 or polyester [poly(ethyleneterephthalate) or PET] cooking bags for enclosing plants during collection of volatiles. A push-pull airflow system was used, and volatiles were trapped on Tenax TA and analyzed by gas chromatography after thermal desorption. Low levels of impurities were found for the glass vessel and polyester bags. Nylon bags contained higher levels and more impurities. Recoveries of standards of 10 plant volatiles were measured in static and dynamic systems. In a static air system, there was good recovery only from the glass vessel. In a dynamic system, there was generally good recovery from both the glass vessel and polyester bags. Recoveries of alpha-pinene and (Z)-jasmone were poor throughout. The former was shown to have a very low breakthrough volume on the Tenax TA adsorbent, and the latter may be strongly adsorbed on glass. All three materials were essentially transparent in the IR and visible (photosynthetic) range but with significantly different absorptions in the UV range. In a simulated dynamic entrainment in full sunlight, internal vessel temperatures were higher than ambient by up to 9.5 degrees C in the glass vessel and 7.5 degrees C in the polyester bag. Lower increases in temperature relative to ambient (<1 degrees C) were recorded when entrainments were conducted in the shade. In a field trial, the profiles of volatiles collected from an apple tree infested with rosy apple aphid using a glass vessel and a polyester bag were similar. Polyester bags are recommended as more convenient than glass vessels for the enclosure of plants during the collection of volatiles.

Adsorption↗
PubMed1990

Small pial vessels, but not choroid plexus, exhibit specific biochemical correlates of functional cholinergic innervation.

In an attempt to provide the biochemical foundations for a putative cholinergic innervation of small pial vessels and choroid plexus, we have assessed their ability to specifically accumulate choline, synthesize and release acetylcholine (ACh) in response to depolarization. Our results show that both small pial vessels and choroid plexus avidly accumulate choline via a sodium-dependent mechanism which could be inhibited by hemicholinium-3 (IC50 in pial vessels = 47.8 microM). Light microscopic examination of radioautographs from vessels incubated with [3H]choline revealed two distinct sites of accumulation in the vessel wall. One site probably corresponded to nerve terminals and the other was closely associated with the endothelial cells. In small pial vessels, a major proportion (60%-70%) of the choline acetyltransferase (ChAT) activity could be inhibited by 4-naphthylvinylpyridine (4-NVP), a potent inhibitor of neuronal ChAT; and, following either K+ or veratridine depolarization, a Ca2(+)-dependent release of authentic [3H]ACh could be measured. In contrast, the choroid plexus exhibited a rather low ChAT activity which was not inhibited by 4-NVP and no release of ACh could be detected in this tissue following depolarization. Altogether, the results of the present study show that (1) small pial vessels exhibit all the most selective biochemical markers that are characteristic of cholinergic nerves; (2) [3H]choline in pial vessels can be accumulated in non-neuronal elements which probably correspond to the endothelial cells; and (3) the choroid plexus failed to exhibit convincing biochemical markers that would attest in favor of a functional cholinergic innervation.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

Early ultrastructural changes in blood-brain barrier vessels of the rat embryo.

The blood-brain barrier (BBB) in fetal rat brain has been shown by others to be more permeable to a variety of blood-borne solutes than the BBB in adults. We used ultrastructural morphometric methods to measured the density of putative vascular pores between the ages of embryonic day (E) 11 and birth to determine the structural basis for this relatively high permeability. We found that fenestrations, that are frequent at E11, declined rapidly and were last seen at E13 in intraparenchymal vessels and at E17 in pial vessels. Interendothelial junctions in fetal brain contained expanded clefts suggestive of paracellular channels at all ages examined, although they disappear after birth. Both of these features likely contribute to high fetal BBB permeability, but endothelial vesicles probably do not. The central nervous system is vascularized by ingrowth of capillary sprouts from the perineurial vascular plexus. Invading capillaries express BBB features in response to inductive signals from the surrounding neural tissue. We compared early ultrastructural changes in perineurial vessels, which are separated from neural tissue by a sizeable perivascular space, with those in intraneural vessels, which are totally enveloped by neural tissue, to determine whether the inductive interaction requires close cellular contact. For the most part, the perineurial and intraneural vessels matured in parallel. Furthermore, cerebellar vessels developed in parallel with cerebral vessels, even though they did not invade neural tissue until a comparatively late stage. These results suggest that intimate contact between neural tissue and vessel walls is not a requirement for BBB expression.

Animals↗
PubMed1996

Identification of nitric oxide synthases in isolated bovine brain vessels.

We have studied the presence of neuronal nitric oxide synthase (nNOS) and endothelial nitric oxide synthase (eNOS) in parenchymal and pial bovine cerebral vessels by using western blot analysis. The different vessel structures were analysed by microscopic observation and their biochemical features determined by using gamma-glutamiltranspeptidase (gamma-GTP) as an endothelial marker and alpha-smooth muscle actin (alpha-SMA) as a smooth muscle cell marker. nNOS could not be found in parenchymal vessels, being present only in pial vessels; eNOS was present in all vessel-fractions studied, albeit a different distribution was found. Thus, the eNOS is more abundant in the parenchymal vessels which are associated with smooth muscle cells whereas both pial vessels and brain microvessels, almost devoid of actin, show extremely low levels. Two main conclusions can be obtained: first, nNOS is exclusively restricted to pial vessels and, second, eNOS is present in endothelial cells which are in association with smooth muscle cells.

Animals↗
PubMedDate not supplied

Effect of age on blood vessels and neurovascular appositions in the rat dentate fascia.

Rats aged 3, 9, 24 and 30 months were used in this study. We show increased basal lamina thickening and increased mitochondrial presence in walls of capillaries and not in walls of large vessel populations with age. This suggests that age selectively affects capillary structure. Ultrastructural differences between capillaries and two types of large vessels are reported and discussed in terms of their probable functional significance. In particular it was noted that there are more axon terminals, axons and dendrites adjacent to capillaries than to large vessels and that this was unaffected by increasing age. It is not clear whether the proximity of neuronal processes to a vessel wall serves a function, however, the larger number adjacent to capillaries than to large vessels indicates a more significant role for them in capillary rather than in large vessel function. Since increasing age did not alter the number of neuronal processes adjacent to vessels, age-related compromises in vessel function may be unrelated to neuronal regulation. The age-related changes are discussed as possible vascular markers for the aging brain.

Aging↗
PubMed1985

Production of prostacyclin (PGI2) and thromboxane A2 (TXA2) by vessels draining and not-draining benign and malignant tumours of the breast.

The production of PGI2 (determined by bioassay) and TXB2 (determined by radioimmunoassay) was studied in the supernatant solutions obtained after incubation of vessel rings prepared from veins draining and not draining benign and malignant tumours of the breast. A significant increase (p less than 0.01) was found in the production of PGI2 by vessels draining the malignant tumours as compared to those not draining such tumours or vessels draining benign tumours. The changes in PGI2, and the tendency for TXB2 to be higher in vessels draining malignant tumours, were in the same direction so that they balanced out when the ratio PGI2/TXB2 was calculated: in consequence no significant changes in this ratio were found in malignant tumours as compared to the benign. A significant difference (p less than 0.01) was observed in the ratios of vessels draining tumours:vessels not draining tumours between malignant and benign tumours in relation to the production of PGI2. The present data demonstrate that the production of PGI2 by vessels draining malignant tumours of the breast is different to that obtained with vessels from patients with benign tumours, although the mechanism responsible for this difference is not known.

Adult↗
PubMed1995

Is the clustering of beta-amyloid (A beta) deposits in the frontal cortex of Alzheimer patients determined by blood vessels?

The clustering pattern of diffuse, primitive and classic beta-amyloid (A beta) deposits was studied in the upper laminae of the frontal cortex of 9 patients with sporadic Alzheimer's disease (AD). A beta stained tissue was counterstained with collagen type IV antiserum to determine whether the clusters of A beta deposits were related to blood vessels. In all patients, A beta deposits and blood vessels were clustered, with in many patients, a regular periodicity of clusters along the cortex parallel to the pia. The classic A beta deposit clusters coincided with those of the larger blood vessels in all patients and with clusters of smaller blood vessels in 4 patients. Diffuse deposit clusters were related to blood vessels in 3 patients. Primitive deposit clusters were either unrelated to or negatively correlated with the blood vessels in six patients. Hence, A beta deposit subtypes differ in their relationship to blood vessels. The data suggest a direct and specific role for the larger blood vessels in the formation of amyloid cores in AD.

Aged↗
PubMed1993

Transformation of coronary artery aneurysm to obstructive lesion and the role of collateral vessels in myocardial perfusion in patients with Kawasaki disease.

OBJECTIVES: The aim of this study was to examine the transformation of coronary artery aneurysms to obstructive lesions and to assess the role of collateral vessels in patients with Kawasaki disease. BACKGROUND: Coronary artery aneurysms, especially giant aneurysms, are known to become obstructive lesions in patients with Kawasaki disease. However, the process of transformation is not yet clear. METHODS: Thirty patients (average age 9.9 years) with obstructive lesions secondary to Kawasaki disease underwent repeated coronary artery angiography and thallium myocardial scintigraphy over a mean period of 7.7 years after the acute onset of Kawasaki disease. RESULTS: In the 27 patients who were enrolled in the acute phase of the disease because of coronary artery aneurysms, the later transformation to obstructive lesions was not significantly different between the 61 large and 6 medium-sized aneurysms. Obstructive transformation of aneurysms was more rapid in the right than in the left coronary artery (p < 0.001). From the last coronary angiogram obtained, the obstructive lesions were classified as localized stenosis > 90% in 10 vessels, occlusions in 6 vessels and segmental stenosis in 26 vessels. Both localized and segmental stenosis occurred significantly more often in the left anterior descending and the right coronary artery than in other vessels (p < 0.05). The incidence of collateral vessels was significantly correlated with a younger age at onset of Kawasaki disease, especially in patients with segmental stenosis (p < 0.001). Collateral vessels did not develop in the presence of localized stenosis regardless of the occurrence of myocardial ischemia. All occluded vessels had collateral development regardless of the presence of myocardial infarction. CONCLUSIONS: The treatment of localized stenosis may play an important role in preventing myocardial infarction in the chronic phase of Kawasaki disease.

Acute Disease↗
PubMed2005

Vessel tortuosity and brain tumor malignancy: a blinded study.

RATIONALE AND OBJECTIVES: Malignancy provokes regional changes to vessel shape. Characteristic vessel tortuosity abnormalities appear early during tumor development, affect initially healthy vessels, spread beyond the confines of tumor margins, and do not simply mirror tissue perfusion. The ability to detect and quantify tortuosity abnormalities on high-resolution magnetic resonance angiography (MRA) images offers a new approach to the noninvasive diagnosis of malignancy. This report evaluates a computerized, statistical method of analyzing the shapes of vessels extracted from MRA in diagnosing cancer. MATERIALS AND METHODS: The regional vasculature of 34 healthy subjects was compared with the tumor-associated vasculature of 30 brain tumors before surgical resection. The operator performing the analysis was blinded to the diagnosis. Vessels were segmented from an MRA of each subject, a region of interest was defined in each tumor patient and was mapped to all healthy controls, and a statistical analysis of vessel shape measures was then performed over the region of interest. Many difficult cases were included, such as pinpoint, hemorrhagic, and irradiated tumors, as were hypervascular benign tumors. Tumors were identified as benign or malignant on the basis of histological evaluation. RESULTS: A discriminant analysis performed at the study's conclusion successfully classified all but one of the 30 tumors as benign or malignant on the basis of vessel tortuosity. CONCLUSIONS: Quantitative, statistical measures of vessel shape offer a new approach to the diagnosis and staging of disease. Although the methods developed under the current report must be tested against a new series of cases, initial results are promising.

Adult↗
PubMed2005

How can a massive training artificial neural network (MTANN) be trained with a small number of cases in the distinction between nodules and vessels in thoracic CT?

RATIONALE AND OBJECTIVES: To demonstrate that a massive training artificial neural network (MTANN) can be adequately trained with a small number of cases in the distinction between nodules and vessels (non-nodules) in thoracic computed tomography (CT) images. MATERIALS AND METHODS: An MTANN is a trainable, highly nonlinear filter consisting of a linear-output multilayer artificial neural network model. For enhancement of nodules and suppression of vessels, we used 10 nodules and 10 non-nodule images as training cases for MTANNs. The MTANN is trained with a large number of input subregions selected from the training cases and the corresponding pixels in teaching images that contain Gaussian distributions for nodules and zero for non-nodules. We trained three MTANNs with different numbers (1, 9, and 361) of training samples (pairs of the subregion and the teaching pixel) selected from the training cases. In order to investigate the basic characteristics of the trained MTANNs, we applied the MTANNs to simulated CT images containing various-sized model nodules (spheres) with different contrasts and various-sized model vessels (cylinders) with different orientations. In addition, we applied the trained MTANNs to nontraining actual clinical cases with 59 nodules and 1,726 non-nodules. RESULTS: In the output images for the simulated CT images by use of the MTANNs trained with small numbers (one and nine) of subregions, model vessels were clearly visible and were not removed; thus, the MTANNs were not trained properly. However, in the output image of the MTANN trained with a large number of subregions, various-sized model nodules with different contrasts were represented by light nodular distributions, whereas various-sized model vessels with different orientations were dark and thus were almost removed. This result indicates that the MTANN was able to learn, from a very small number of actual nodule and non-nodule cases, the distinction between nodules (spherelike objects) and vessels (cylinder-like objects). In nontraining clinical cases, the MTANN was able to distinguish actual nodules from actual vessels in CT images. For 59 actual nodules and 1,726 non-nodules, the performance of the MTANN decreased as the number of training samples (subregions) in each case decreased. CONCLUSIONS: The MTANN can be trained with a very small number of training cases (10 nodules and 10 non-nodules) in the distinction between nodules and non-nodules (vessels) in CT images. Massive training by scanning of training cases to produce a large number of training samples (input subregions and teaching pixels) would contributed to a high generalization ability of the MTANN.

Algorithms↗
PubMed2004

Is the use of a 200 ml vessel suitable for dissolution of low dose drug products?

This work evaluated the use of a commercially available 200 ml vessel for dissolution of five drug products with various solubilities. Each of the five drug products (four with USP monographs and one proprietary tablet formulation) was run at four different conditions (USP 25 monograph, six dosage units in single 1l vessel, 200 ml at the USP Monograph speed, and 200 ml at calculated paddle speed which matches the hydrodynamics of the USP vessel). Six dosage units in a single vessel were used as a comparison to increase the drug concentration for dissolution testing. Due to the different dissolution hydrodynamics, drug dissolution from the dosage forms was slower using the 200 ml conversion kit than when the USP method with a 1l vessel was used. However, use of the 200 ml vessel at higher paddle speeds calculated by the power/volume equation, yielded similar results as the monograph method. Thus, it appears that using the power/volume ratio calculation to obtain comparable hydrodynamics lends utility to the 200 ml vessel as a means for characterizing the dissolution profile of low dose solid oral drug products. The results of the multiple dosage units per vessel also gave similar results to that of the USP monograph method.

Capsules↗
PubMed2005

Significance of source and size in the mechanical response of human cerebral blood vessels.

Cerebral blood vessels are frequently damaged in traumatic brain injury. Mechanical properties of fresh human cerebral vessels obtained through surgeries have been reported. Because surgical sources of human specimens are rare and produce a limited amount of material, we sought to compare the properties of more readily available cerebral arteries and veins obtained from cadavers to fresh vessel data. Additionally, because the previous study was limited to small vessels available in surgery, it was unknown how generally applicable the results were to larger cerebral arteries and veins. In the current study, large and small cerebral vessels from autopsy were stretched axially. Data from these and similar tests on fresh vessels were combined to determine the significance of source and size on mechanical properties. Structural comparisons of histological samples were additionally utilized to characterize differences. Results indicate that specimens from autopsy and surgery behave similarly except that vessels from autopsy tend to be less extensible. While tests on large vessels were limited, small arteries obtained from autopsy tended to be slightly stiffer than large arteries. In contrast, bridging veins from cadavers were typically stiffer and stretched less before structural failure than cortical veins from the same source. These effects are, however, secondary to differences identified between arteries and veins in the previous study.

Adult↗
PubMed2005

A technique to detect and to quantify fasciocutaneous blood vessels in small laboratory animals ex vivo.

PURPOSE: A microangiographical technique is described, which allows visualization of small and capillary blood vessels and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. MATERIALS AND METHODS: The left carotid artery of 20 nu/nu mice was cannulated (26 gauge) and a mixture of gelatin, bariumsulfate, and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units [SU] by computer program. RESULTS: With the described microangiography method, fasciocutaneous blood vessels down to capillary size level can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Comparable results may be obtained by calculating the microvascular area index (MAI) and the microvascular length index (MLI), related to the ROIs size. Identical ROIs showed a high reproducibility for measured [SU] < 0.01 +/- 0.0012%. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge, and modern digital image technology, we were able to visualize small and capillary blood vessels even in small laboratory animals. By using our own computer analytical program, quantification of vessels was reliable, highly reproducible, and fast.

Angiography↗
PubMed2007

Color Doppler US pulmonary artery vessel signal: a sign for predicting the benign lesions.

The lung cancer blood supply originates from the bronchial artery. If vessel signals within pulmonary lesions can be confirmed to be those of the pulmonary artery, color Doppler ultrasound (US) should be able to predict and differentiate benign lesions from lung cancers. Two hundred sixty-four patients with abutting thoracic lesions (including 125 lung cancers and 139 benign lesions) underwent color Doppler US examinations. A pulsatile flow, with the vessel signal length on sonographic appearance > or =1 cm demonstrated by color Doppler US, was arbitrarily defined as a pulmonary artery vessel signal. Of the 264 thoracic lesions, 73 (58%) lung cancers and 107 (77%) benign lesions had detectable color Doppler US pulsatile flow vessel signals. Analyzing the pulsatile flow vessel signals, the color Doppler US pulmonary artery vessel signal was present in 74 (53%) benign lesions, but was found in only two (2%) lung cancers of a specific alveolar cell carcinoma with lobar consolidation. Using the pulmonary artery vessel signal, color Doppler US can be valuable in predicting and differentiating benign lesions from lung cancers (p < 0.0001, sensitivity = 0.53, specificity = 0.98 and positive likelihood ratio 26.5). In conclusion, color Doppler US pulmonary artery vessel signal sign is useful in predicting and differentiating benign lesions from lung cancers.

Adolescent↗
PubMed1998

Relation between abrupt vessel closure and the anticoagulant response to heparin or bivalirudin during coronary angioplasty.

The dosing of anticoagulants during coronary angioplasty is commonly guided by measurements of activated clotting time (ACT), but the usefulness of these measurements remains uncertain. The Hirulog Angioplasty Study was a randomized, double-blind comparison of heparin versus bivalirudin in 4,312 patients undergoing angioplasty for unstable or postinfarction angina. In 4,098 of the patients randomized, the balloon was inflated. All patients had ACT measurements 5 minutes after a weight-adjusted bolus of heparin or bivalirudin, and patients undergoing complicated or prolonged angioplasty procedures lasting >45 minutes had additional ACT measurements to guide further anticoagulant therapy. The analysis presented in this article evaluated the relation between the initial or maximum ACT measurements and the risk of abrupt vessel closure during heparin or bivalirudin therapy. Abrupt vessel closure occurred in 189 of 2,039 patients (9.3%) treated with heparin, and in 189 of 2,059 patients (9.2%) treated with bivalirudin (p = not significant). An inverse relation between the risk of abrupt closure and initial ACT measurements was observed in heparin-treated patients: the probability of abrupt vessel closure decreased by 1.3% for every 10-second increase in the initial ACT response to heparin therapy (p = 0.02). Among 903 of 2,039 heparin-treated patients (44%) who received additional heparin for prolonged or complicated procedures, the likelihood of abrupt vessel closure also decreased by 1.1% for every 10-second increase in ACT (p = 0.04). In 2,059 patients treated with bivalirudin, however, no relation between the probability of abrupt vessel closure and the initial ACT measurement was observed (p = 0.88). From the results it was concluded that when heparin is used during coronary angioplasty, the risk of abrupt vessel closure is related to patient responsiveness to anticoagulation therapy. Heparin-resistant patients are more likely to experience abrupt vessel closure than patients who have high ACT values in response to initial therapy. In contrast, when bivalirudin is used during coronary angioplasty, a flat relation between the risk of abrupt vessel closure and ACT values is seen. This suggests that the direct thrombin inhibitor, bivalirudin, provides more even levels of anticoagulation and more predictable levels of risk of abrupt closure than heparin. Measurements of ACT may not be necessary when bivalirudin is used during coronary angioplasty.

Angina Pectoris↗
PubMed2000

Resistance vessel endothelial function in healthy humans during transient postprandial hypertriglyceridemia.

A single high-fat meal transiently impairs conduit vessel endothelial function. We tested the hypothesis that transient moderate hypertriglyceridemia by consumption of a high-fat meal impairs forearm resistance vessel endothelial function. Fifteen healthy persons consumed isocaloric high- and low-fat meals (900 calories, 50 and 4 g of fat, respectively) on 2 separate days. Endothelial function in forearm resistance vessels was assessed using blood flow responses to local intra-arterial infusion of nitroprusside, acetylcholine, bradykinin, and verapamil from 1 to 3 hours after the meal. Serum triglycerides increased from 112 +/- 15 mg/dl preprandially to 165 +/- 20 mg/dl 4 hours after the high-fat meal, which was a significantly larger increase than levels after the low-fat meal (p = 0.01). Total cholesterol, high-density lipoprotein, low-density lipoprotein, and very low density lipoprotein (VLDL) cholesterol concentrations did not change. There was no difference between high- and low-fat meals in vasodilation to the endothelium-dependent agents acetylcholine (low fat, 337 +/- 47%; high fat, 356 +/- 88%; p = 0.81) and bradykinin (low fat, 312 +/- 39%; high fat, 403 +/- 111%; p = 0.28), or to the endothelium-independent vasodilators nitroprusside (low fat, 313 +/- 27%; high fat, 355 +/- 42%; p = 0.31) and verapamil (low fat, 292 +/- 48%; high fat, 299 +/- 36%; p = 0.18). Thus, transient hypertriglyceridemia due to a high-fat meal does not impair resistance vessel endothelial function. These data contrast with previous studies in conduit vessels that showed substantial endothelial dysfunction. Therefore, although high-fat intake may contribute to large artery atherosclerosis, it probably does not predispose to hypertension or ischemia through resistance vessel dysfunction. The results suggest that the mechanism by which triglyceride-rich lipoproteins impair endothelial function in conduit vessels is not operative in resistance vessels.

Acetylcholine↗
PubMed2004

Higher vessel densities in retinoblastoma with local invasive growth and metastasis.

In this study, the importance of angiogenesis (the growth of new blood vessels from existing ones) for the growth of retinoblastoma was investigated by a retrospective immunohistochemical analysis. An individual vessel index for each tumor was determined using the endothelial-specific antibody CD 31 for vessel staining. The obtained data were correlated with clinical features, pathohistological characteristics, and the presence of metastasis. In 107 retinoblastomas collected between 1980 and 1990, we found no difference in the vessel densities between uni- and bilateral retinoblastomas (P = 0.41). However, tumors that had invaded the chorioid and/or the optic nerve statistically showed higher vessel densities than tumors without local invasive growth (P = 0.05 and P = 0.024). A tendency of higher vessel densities in retinoblastomas presenting with metastasis at the time of diagnosis was observed (P = 0.11). Based on this observation, we proceeded to examine all retinoblastomas presenting with metastasis at the time of diagnosis. These included patients that were treated between 1968 and 1993. The 18 investigated retinoblastomas had significantly higher vessel densities than all other retinoblastomas presenting without metastasis (P = 0.025). Our data indicate that in retinoblastoma, blood vessels are essential for local and systemic invasive growth. Therefore, an anti-angiogenic therapy could be considered in the multimodal therapy concept for retinoblastomas with invasive growth, both locally and systemically.

Endothelium, Vascular↗
PubMed1997

Distribution of muscarinic receptors on the endothelium of cortical vessels in the rat brain.

Functional and pharmacological studies have suggested that there are muscarinic receptors (mAChRs) on the endothelial cells of major cerebral arteries, while recent immunological studies indicate that there are no mAChRs on the endothelium of brain capillaries. This difference may be because the distribution of mAChR on the endothelium varies with the type of vessel. This paper examines the distribution of mAChR on the vascular endothelium along intraparenchymal blood vessels in the rat brain by immunolabelling and laser confocal microscopy. Sections were immunostained by combinations of an anti-mAChR antibody (M35) with antibodies to endothelial (anti-GLUT1), or to smooth muscle markers (anti-actin). Antibody labellings were detected with fluorescent second antibodies. Most of the penetrating vessels bore mAChR immunolabelling which coincided over almost all the vessel surface with endothelial labelling. The mAChR immunolabelling was less widespread over the endothelium on the medium sized vessels (diameter < 50 microm) and only 50% of these vessels had mAChR staining on the endothelium. There was no mAChR immunostaining on the endothelium of the capillaries. In contrast with the basilar artery, there was no mAChR immunolabelling on the smooth muscle layer of the intracortical vessels. These data indicate that the intensity of mAChR immunolabelling decreases along the vascular tree from large conducting vessels to capillaries.

Actins↗