Vasomotion of basilar arteries in vivo

1990 ◽  
Vol 258 (6) ◽  
pp. H1829-H1834 ◽  
Author(s):  
K. Fujii ◽  
D. D. Heistad ◽  
F. M. Faraci
Keyword(s):  
Moderate Hypertension ◽  
Vessel Diameter ◽  
Base Line ◽  
Large Artery ◽  
Cranial Window ◽  
Basilar Arteries ◽  
The Mean ◽  
Rhythmic Change ◽  
The Brain

Vasomotion is a rhythmic change in vascular caliber that has been described in vivo mainly in peripheral arterioles. In this study, we have characterized vasomotion in a large artery of the brain in vivo. In anesthetized rats, spontaneous vasomotion was observed in 38 of 47 basilar arteries visualized through a cranial window. Base-line arterial diameter was 259 +/- 9 (means +/- SE) microns. Under control conditions, the frequency of vasomotion was 4.8 +/- 0.2 cycles/min, and the amplitude was 19 +/- 2% of the mean diameter. Vasomotion usually occurred simultaneously along the entire length of the vessel, but in some arteries it propagated in either direction. Moderate hypertension (phenylephrine) or vasoconstriction induced by topical application of serotonin, vasopressin, or the thromboxane analogue U 46619 increased the frequency of vasomotion. Moderate hypotension or vasodilation induced by nitroglycerin, adenosine, or acetylcholine decreased the frequency. Marked hypertension, hypotension, or vasodilatation abolished vasomotion. Thus vasomotion of the basilar artery in vivo 1) is common and of relatively large amplitude, 2) does not seem to be driven by a single pacemaker, and 3) is dependent on vessel diameter or vasomotor tone.

Effect of protein kinase C inhibitors on endothelin- and vasopressin-induced constriction of the rat basilar artery

1992 ◽  
Vol 263 (6) ◽  
pp. H1643-H1649 ◽  
Author(s):  
M. A. Murray ◽  
F. M. Faraci ◽  
D. D. Heistad
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Basilar Artery ◽  
Arginine Vasopressin ◽  
Vessel Diameter ◽  
Pkc Inhibitor ◽  
Cranial Window ◽  
Kinase C ◽  
Basilar Arteries

The goal of this study was to determine whether inhibitors of protein kinase C (PKC) attenuate constrictor responses of the basilar artery in vivo to endothelin and arginine vasopressin. In anesthetized rats, the diameter of basilar arteries was measured through a cranial window [control diameter 218 +/- 3 (SE) microns]. Vessel diameter was measured during topical application of agonists and antagonists. Sphingosine (10(-6) M), a PKC inhibitor that binds to the regulatory site of PKC, attenuated vasoconstriction in response to endothelin (10(-9), 10(-8), and 10(-7) M) and vasopressin (10(-9) and 10(-8) M). H-7 (10(-9) M), a PKC inhibitor that binds to the catalytic site of PKC, also inhibited vasoconstriction in response to endothelin and vasopressin. Sphingosine and H-7 did not affect baseline diameter and did not attenuate vasoconstriction in response to prostaglandin (PG) F2 alpha. The V1 antagonist [d(CH2)5Tyr(Me)]arginine vasopressin (10(-8) M) significantly inhibited constriction in response to vasopressin (10(-9) and 10(-8) M) but not PGF2 alpha (10(-6) M). These observations suggest that activation of PKC may contribute to endothelin-induced constriction of the basilar artery in vivo and that PKC may also be a mediator of V1-receptor-mediated constriction of the basilar artery in response to vasopressin.

Direct Effects of α1-and α2-AdrenergicAgonists on Spinal and Cerebral Pial Vessels in Dogs 

1999 ◽  
Vol 91 (2) ◽  
pp. 479-485 ◽  
Author(s):  
Hiroki Iida ◽  
Hiroto Ohata ◽  
Mami Iida ◽  
Yukinaga Watanabe ◽  
Shuji Dohi
Keyword(s):  
Topical Administration ◽  
Vessel Diameter ◽  
Dependent Manner ◽  
Adrenergic Agonists ◽  
Concentration Dependent Manner ◽  
Cranial Window ◽  
Pial Vessels ◽  
Cerebral Arterioles ◽  
Pial Vessel

Background The effects of adrenergic agonists, often used as local anesthetic additives or spinal analgesics, on spinal vessels have not been firmly established. The authors investigated the effects of alpha2- and alpha1-adrenergic agonists on spinal and cerebral pial vessels in vivo. Methods Pentobarbital-anesthetized dogs (n = 28) were prepared for measurement of spinal pial-vessel diameter in a spinal-window preparation. The authors applied dexmedetomidine, clonidine, phenylephrine, or epinephrine in three different concentrations (0.5, 5.0, and 50 microg/ml; [2.1, 1.9, 2.5, and 2.3] x [10(-6), 10(-5), and 10(-4)] M, respectively) under the window (one drug in each dog) and measured spinal pial arteriolar and venular diameters in a sequential manner. To enable the comparison of their effects on cerebral vessels, the authors also administered these drugs under a cranial window. Results On topical administration, each drug constricted spinal pial arterioles in a concentration-dependent manner. Phenylephrine and epinephrine induced a significantly larger arteriolar constriction than dexmedetomidine or clonidine at 5 microg/ml (8%, 11%, 0%, and 1%, respectively). Spinal pial venules tended to be less constricted than arterioles. In cerebral arterioles, greater constrictions were induced by dexmedetomidine and clonidine than those induced by phenylephrine and epinephrine (14%, 8%, 0%, and 1%, respectively). Cerebral pial venules tended to exhibit larger constrictions than cerebral arterioles (unlike in spinal vessels). Conclusion Dexmedetomidine and clonidine constricted spinal vessels in a concentration-dependent manner, but such vasoconstrictions were smaller than those induced by phenylephrine and epinephrine.

scholarly journals Chronic cranial window for photoacoustic imaging: a mini review

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yongchao Wang ◽  
Lei Xi
Keyword(s):  
Surgical Procedure ◽  
Brain Cortex ◽  
Photoacoustic Imaging ◽  
Field Of View ◽  
Cranial Window ◽  
Biological Compatibility ◽  
Technical Details ◽  
The Brain

AbstractPhotoacoustic (PA) microscopy is being increasingly used to visualize the microcirculation of the brain cortex at the micron level in living rodents. By combining it with long-term cranial window techniques, vasculature can be monitored over a period of days extending to months through a field of view. To fulfill the requirements of long-term in vivo PA imaging, the cranial window must involve a simple and rapid surgical procedure, biological compatibility, and sufficient optical-acoustic transparency, which are major challenges. Recently, several cranial window techniques have been reported for longitudinal PA imaging. Here, the development of chronic cranial windows for PA imaging is reviewed and its technical details are discussed, including window installation, imaging quality, and longitudinal stability.

scholarly journals Dual Orexin and MCH neuron-ablated mice display severe sleep attacks and cataplexy

2019 ◽  
Author(s):  
Chi Jung Hung ◽  
Daisuke Ono ◽  
Thomas S. Kilduff ◽  
Akihiro Yamanaka
Keyword(s):  
Spectral Power ◽  
Nrem Sleep ◽  
Functional Interaction ◽  
Neuronal Populations ◽  
Orexin Neuron ◽  
Melanin Concentrating Hormone ◽  
The Mean ◽  
The Brain ◽  
Theta Range

SummaryOrexin/hypocretin-producing and melanin-concentrating hormone-producing (MCH) neurons are co-extensive in the tuberal hypothalamus and project throughout the brain to regulate sleep/wakefulness. Ablation of orexin neurons in mice decreases wakefulness and results in a narcolepsy-like phenotype, whereas ablation of MCH neurons increases wakefulness. Since it is unclear how orexin and MCH neurons interact to regulate sleep/wakefulness, we generated conditional transgenic mice in which both orexin and MCH neurons could be ablated. Double-ablated mice exhibited increased wakefulness and decreased both rapid eye movement (REM) and non-REM (NREM) sleep. The total time in cataplexy and the mean cataplexy bout duration increased significantly in double-ablated mice compared with orexin neuron-ablated mice, suggesting that MCH neurons normally suppress cataplexy and that compromised MCH neurons may exacerbate symptoms in some narcoleptic patients. Double-ablated mice also showed frequent sleep attacks with elevated spectral power in the delta and theta range during wakefulness, a state with EEG characteristics indistinguishable from the transition from NREM into REM sleep. Together, these results indicate a functional interaction between orexin and MCH neurons in vivo that suggests the synergistic involvement of these neuronal populations in the sleep/wakefulness cycle.

scholarly journals TMOD-37. IN VIVO COMPRESSION AND IMAGING FOR CAUSAL STUDIES OF MECHANICAL FORCES IN THE BRAIN

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii235-ii236
Author(s):  
Meenal Datta ◽  
Hadi Nia ◽  
Giorgio Seano ◽  
Sylvie Roberge ◽  
Peigen Huang ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Biological Effects ◽  
Neurological Dysfunction ◽  
Normal Brain ◽  
Mechanical Forces ◽  
Mechanistic Studies ◽  
Cranial Window ◽  
Solid Stress ◽  
The Brain

Abstract Clinicians have long observed the effects of abnormal mechanical forces – edema (fluid pressure) in particular – in brain tumors and the surrounding normal brain tissue. However, it was not previously possible to dissect the direct effects of solid stress (i.e., “mass effect”), a mechanopathology resulting from solid components of the tumor tissue, on the brain from the biological and physiological adverse effects exerted by cancer cells. We recently developed for the first time an in vivo compression device that allows for causal and mechanistic studies that delineate the solid mechanical forces of a tumor growing in the brain from its biological effects. The brain poses a unique anatomical consideration of abnormal mechanical forces due to its physical confinement by the skull. We adapted standard transparent cranial windows normally used for intravital imaging studies in mice to include a tunable screw for controlled and acute or chronic compression and decompression in the brain. This compressive cranial window allows for longitudinal imaging of the surrounding brain tissue (cortex or cerebellum) over time (weeks or months) as the screw is lowered further into the brain tissue to recapitulate tumor growth-induced solid stress. Using this device, we have demonstrated that solid stress is causally linked to vascular and neurological dysfunction in the brain. We have also been able to utilize this preclinical system to screen for effective therapeutic interventions to reduce solid stress-induced neuronal death and improve neurological function. Beyond cancer, this technique can be used to study a variety of diseases or disorders that present with abnormal solid masses in the brain, including cysts and benign growths. Thus, mechanistic studies enabled by the compressive cranial window can elucidate the role of mechanics in brain tumor progression, and reveal novel targets for treatment.

scholarly journals Reactivity of Rat Pial Arterioles and Venules to Adenosine and Carbon Dioxide: With Detailed Description of the Closed Cranial Window Technique in Rats

1986 ◽  
Vol 6 (1) ◽  
pp. 34-41 ◽  
Author(s):  
Seiji Morii ◽  
Al C. Ngai ◽  
H. Richard Winn
Keyword(s):  
Carbon Dioxide ◽  
Video Camera ◽  
Vessel Diameter ◽  
Resolving Power ◽  
Camera System ◽  
Cranial Window ◽  
Window Technique ◽  
Adenosine Concentration ◽  
Pial Arterioles

This study describes a closed cranial window technique that allows the observation and measurement of rat pial arterioles and venules in situ. The resolving power of this system is 1–2 μm. Using this sensitive technique, we characterized the responses to 7% carbon dioxide inhalation and adenosine in arterioles (10–70 μm) and venules (15–100 μm). During carbon dioxide inhalation, larger arterioles (>40μm) dilated more than smaller arterioles (<20 μm). There was limited vasoreac-tivity of pial venules during CO2 inhalation. Dilation of arterioles was initially observed with an adenosine concentration of 10−8 M. Almost a twofold increase in diameter was noted at 10−3 M. In contrast to the effect of CO2 inhalation, the degree of dilation with topical application of adenosine was not size dependent. Pial venules did not respond to adenosine. The technique for observation of pial vessels using the closed cranial window and for measurement of vessel diameter by video camera system microscopy is a powerful tool for studying in vivo the cerebral circulation in the rat.

Stimulation of ciliary beat frequency by autonomic agonists: in vivo

1988 ◽  
Vol 65 (2) ◽  
pp. 971-981 ◽  
Author(s):  
L. B. Wong ◽  
I. F. Miller ◽  
D. B. Yeates
Keyword(s):  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Ciliary Activity ◽  
Base Line ◽  
Muscarinic Cholinergic ◽  
The Mean ◽  
Beta 2 ◽  
Ciliary Beat

beta 2-Adrenergic bronchodilator and muscarinic cholinergic bronchoconstrictor agonists both stimulate ciliary activity in vitro. To test the hypothesis that increases in autonomic activity would result in increases in ciliary beat frequency (CBF) in vivo, a correlation analysis heterodyne laser light-scattering system was developed and validated to measure the stimulating effects of sympathomimetic and parasympathomimetic agonists on tracheal CBF in intact, anesthetized beagles. The mean baseline CBF from 42 studies of 274 measurements in 9 (5 male and 4 female) adult beagles was 6.6 +/- 1.1 Hz. The stimulating effects of a beta 2-adrenergic agonist, fenoterol, and a muscarinic cholinergic agonist, methacholine, on CBF were studied on four and eight beagles, respectively. The studies were randomized and blinded. Aerosolized 10(-5) M fenoterol stimulated the CBF from the base line of 6.8 +/- 2.5 to 32.0 +/- 17.9 Hz in four dogs. Aerosolized methacholine stimulated the CBF from the base line of 5.8 +/- 0.7 to 9.4 +/- 3.0 Hz for 10(-8) M, and to 12.6 +/- 3.1 Hz for 10(-6) M in eight dogs. These are the first data obtained in intact animals that demonstrate CBF in the lower respiratory tract is regulated by autonomic agonists.

Concentration profile of blood platelets differs in arterioles and venules

1992 ◽  
Vol 262 (4) ◽  
pp. H1217-H1223 ◽  
Author(s):  
B. Woldhuis ◽  
G. J. Tangelder ◽  
D. W. Slaaf ◽  
R. S. Reneman
Keyword(s):  
Vessel Wall ◽  
Unit Volume ◽  
Dextran Sulfate ◽  
Blood Platelets ◽  
Median Plane ◽  
Vessel Diameter ◽  
Mean Values ◽  
Acridine Red ◽  
The Mean

Platelet distribution was investigated in 21 venules (V) and 10 arterioles (A) of the rabbit mesentery (vessel diam 15-33 microns). Circulating platelets were labeled in vivo with the dye acridine red and observed with fluorescence video microscopy. Only platelets flowing in a thin (5-7 microns) optical section located about the median plane of the vessel were used. The relative position of each platelet, i.e., the distance of its centroid to the left vessel wall divided by the local vessel diameter, was determined. In addition, in 10 venules leukocyte margination was inhibited by intravenous injection of dextran sulfate (500,000 mol wt; 30 mg/kg body wt). The number of platelets per unit volume (i.e., platelet density) relative to the mean density was significantly higher in the vessel center of V (1.04) than of A (0.55; P less than 0.005). In contrast, near the wall this density was significantly higher in A compared with V. Mean values were as follows: at radial position (R) = 0.9-1.0, 0.30 in A and 0.11 in V (P greater than 0.05); at R = 0.8-0.9, 1.63 in A and 0.84 in V (P less than 0.002); at R = 0.7-0.8, 1.60 in A and 1.36 in V (P greater than 0.05); at R = 0.6-0.7, 1.16 in A and 1.60 in V (P less than 0.02); and at R = 0.5-0.6, 0.92 in A and 1.36 in V (P less than 0.02). These differences in platelet distribution between arterioles and venules are not caused by the presence of leukocyte margination in venules.

In vivo functional antagonism between isoproterenol and bronchoconstrictants in the dog

1987 ◽  
Vol 63 (2) ◽  
pp. 812-819 ◽  
Author(s):  
J. W. Jenne ◽  
T. K. Shaughnessy ◽  
W. S. Druz ◽  
C. J. Manfredi ◽  
R. E. Vestal
Keyword(s):  
Canine Model ◽  
Base Line ◽  
Methacholine Challenge ◽  
Fourfold Increase ◽  
Resistance Increase ◽  
Lung Resistance ◽  
The Mean ◽  
Functional Antagonism

The functional antagonism between isoproterenol and methacholine, histamine and serotonin, as described in vitro in respiratory smooth muscle was explored in vivo in a canine model. Infusions of isoproterenol were administered during brief peaks of bronchospasm produced by aerosolized methacholine and histamine, or during sustained bronchospasm produced by infused serotonin. In eight mongrel dogs anesthetized with pentobarbital sodium, the mean protection by infused isoproterenol against methacholine challenge decreased from 60.6 to 29.1% as the mean lung resistance (RL) was increased from 78 to 232% over base line by a fourfold increase in methacholine (P less than 0.002). In six dogs, the mean protection by isoproterenol against histamine decreased from 55.5 to 26.9% as the opposing RL increased from 80 to 182% over base line with a fourfold increase in histamine (P less than 0.02). However, with serotonin infusions there was only a small 18% mean decrease in protection (P = 0.05), associated with a correspondingly small 37% mean increase in dose of serotonin despite a 269% mean increase in resistance (P = 0.02). In all cases, the loss of protection correlated more closely with the dose of constrictant than the resistance increase over base line. These findings demonstrate in vivo functional antagonism between isoproterenol and the dose of bronchoconstrictant but not necessarily resistance increase per se.

Development in rats of the brain-pituitary-adrenal response to hypoglycemia in vivo and in vitro

1989 ◽  
Vol 257 (5) ◽  
pp. E757-E763 ◽  
Author(s):  
E. P. Widmaier
Keyword(s):  
Base Line ◽  
Adult Rats ◽  
Glucose Levels ◽  
Altered Glucose ◽  
Dose Dependent Fashion ◽  
Adrenal Response ◽  
Old Rats ◽  
The Brain

To clarify the nature of the stress hyporesponsive period that occurs in neonatal rats, the development of the response of the brain-pituitary-adrenal axis to hypoglycemia stress in rats was assessed in vivo and in vitro. Hypothalami were removed from the brains of neonatal (9-35 days postnatal) or adult rats and incubated in vitro for sequential 30-min periods in Krebs buffer for determination of corticotropin-releasing factor (CRF) secretion under conditions of altered glucose concentrations. As expected from previous studies, CRF secretion from adult hypothalami was significantly increased in severely hypoglycemic conditions (0.55 mM glucose) by approximately 50% above base-line values (in 5.5 mM glucose). However, lowering glucose did not elicit an increase in CRF release from hypothalami of rats less than 35 days of age. Hypothalami obtained from rats less than or equal to 24 days old also failed to show consistent secretory responses to potassium depolarization. At 35 days postnatal the response to hypoglycemia was significant and similar to the adult response. To determine if the lack of hypothalamic response to hypoglycemia in vitro could be correlated with the in vivo responses to hypoglycemia, rats aged 4 days to adult were injected intraperitoneally with porcine insulin and killed at different times after injection. Insulin injections lowered plasma glucose levels in fasted 4-day-old rats in a dose-dependent fashion, but a nadir in glucose (approximately 40 mg/dl) was not reached until 90 min; the same treatment produced a nadir in glucose within 30 min in fasted rats 10 days old and older, suggesting that the 4-day-old rats are relatively insulin insensitive.(ABSTRACT TRUNCATED AT 250 WORDS)

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