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Abstract
The cerebral microcirculation undergoes dynamic changes in parallel with the development of neurons, glia, and their energy metabolism throughout gestation and postnatally. Cerebral blood flow (CBF), oxygen consumption, and glucose consumption are as low as 20% of adult levels in humans born prematurely but eventually exceed adult levels at ages 3 to 11 years, which coincide with the period of continued brain growth, synapse formation, synapse pruning, and myelination. Neurovascular coupling to sensory activation is present but attenuated at birth. By 2 postnatal months, the increase in CBF often is disproportionately smaller than the increase in oxygen consumption, in contrast to the relative hyperemia seen in adults. Vascular smooth muscle myogenic tone increases in parallel with developmental increases in arterial pressure. CBF autoregulatory response to increased arterial pressure is intact at birth but has a more limited range with arterial hypotension. Hypoxia-induced vasodilation in preterm fetal sheep with low oxygen consumption does not sustain cerebral oxygen transport, but the response becomes better developed for sustaining oxygen transport by term. Nitric oxide tonically inhibits vasomotor tone, and glutamate receptor activation can evoke its release in lambs and piglets. In piglets, astrocyte-derived carbon monoxide plays a central role in vasodilation evoked by glutamate, ADP, and seizures, and prostanoids play a large role in endothelial-dependent and hypercapnic vasodilation. Overall, homeostatic mechanisms of CBF regulation in response to arterial pressure, neuronal activity, carbon dioxide, and oxygenation are present at birth but continue to develop postnatally as neurovascular signaling pathways are dynamically altered and integrated. © 2021 American Physiological Society. Compr Physiol 11:1-62, 2021.
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D'Alessio C, Ambrosini A, Colonnese C, Pompeo F, Vandenheede M, Pierelli F, Schoenen J. Indomethacin-Responsive Hemicrania Associated with an Extracranial Vascular Malformation: Report of Two Cases. Cephalalgia 2016; 24:997-1000. [PMID: 15482365 DOI: 10.1111/j.1468-2982.2004.00778.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kanu A, Leffler CW. Arachidonic acid- and prostaglandin E2-induced cerebral vasodilation is mediated by carbon monoxide, independent of reactive oxygen species in piglets. Am J Physiol Heart Circ Physiol 2011; 301:H2482-7. [PMID: 21984542 DOI: 10.1152/ajpheart.00628.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Arachidonic acid (AA) and prostaglandin (PG) E(2) stimulate carbon monoxide (CO) production, and AA metabolism is known to be associated with the generation of reactive oxygen species (ROS). This study was conducted to address the hypothesis that CO and/or ROS mediate cerebrovascular dilation in newborn pigs. Experiments were performed on anesthetized newborn pigs with closed cranial windows. Different concentrations of AA (10(-8)-10(-6) M), PGE(2) (10(-8)-10(-6) M), iloprost (10(-8)-10(-6) M), and their vehicle (artificial cerebrospinal fluid) were given. Piglets with PGE(2) and iloprost received indomethacin (5 mg/kg iv) to inhibit cyclooxygenase. AA, PGE(2), and iloprost caused concentration-dependent increases in pial arteriolar diameter. The effects of both AA and PGE(2) in producing cerebral vascular dilation and associated CO production were blocked by the heme oxygenase inhibitor chromium mesoporphyrin (2 × 10(-5) M), but not by the prostacyclin analog, iloprost. ROS inhibitor tempol (SOD mimetic) (1 × 10(-5) M) and the H(2)O(2) scavenger catalase (1,000 U/ml) also do not block these vasodilator effects of AA and PGE(2). Heme-L-lysinate-induced cerebrovascular dilation and CO production was blocked by chromium mesoporphyrin. Hypoxanthine plus xanthine oxidase, a combination that is known to generate ROS, caused pial arteriolar dilation and CO production that was inhibited by tempol and catalase. These data suggest that AA- and PGE(2)-induced cerebral vascular dilation is mediated by CO, independent of ROS.
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Affiliation(s)
- Alie Kanu
- Laboratory for Research in Neonatal Physiology, Department of Physiology, University of Tennessee Health Science Center, Memphis, 38163, USA.
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Fang X, Faraci FM, Kaduce TL, Harmon S, Modrick ML, Hu S, Moore SA, Falck JR, Weintraub NL, Spector AA. 20-Hydroxyeicosatetraenoic acid is a potent dilator of mouse basilar artery: role of cyclooxygenase. Am J Physiol Heart Circ Physiol 2006; 291:H2301-7. [PMID: 16782846 DOI: 10.1152/ajpheart.00349.2006] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
20-Hydroxyeicosatetraenoic acid (20-HETE), an arachidonic acid (AA) metabolite synthesized by cytochrome P-450 omega-oxidases, is reported to produce vasoconstriction in the cerebral circulation. However, we find that like 14,15-epoxyeicosatrienoic acid (14,15-EET), 20-HETE produces dilation of mouse basilar artery preconstricted with U-46619 in vitro. Indomethacin inhibited the vasodilation produced by 20-HETE but not by 14,15-EET, suggesting a cyclooxygenase (COX)-dependent mechanism. Metabolic studies indicated several mechanisms that may play a role in this process. Mouse brain endothelial cells (MBEC) converted 20-HETE to 20-OH-PGE(2), which was as potent as PGE(2) in dilating the basilar artery. 20-HETE also stimulated AA release and PGE(2) and 6-keto-PGF(1alpha) production in MBEC. Furthermore, the basilar artery converted 20-HETE to 20-COOH-AA, which also produced COX-dependent dilation of the basilar artery. 20-COOH-AA increased AA release and PGE(2) and 6-keto-PGF(1alpha) production by the MBEC, but to a lesser extent than 20-HETE. Whereas the conversion of 20-HETE to 20-OH-PGE(2) and production of endogenous prostaglandins probably are primarily responsible for vasodilation, the production of 20-COOH-AA also may contribute to this process.
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Affiliation(s)
- Xiang Fang
- Dept. of Medicine, Harbor Hospital Center, 3001 S. Hanover St., Baltimore MD 21225, USA.
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Pourcyrous M, Bada HS, Blaho KE, Randolph MM, Parfenova H, Mandrell TD, Arheart K, Korones SB, Leffler CW. Chronic prenatal exposure to cocaine alters cerebrovascular responses in newborn pigs. Exp Biol Med (Maywood) 2004; 229:819-25. [PMID: 15337837 DOI: 10.1177/153537020422900815] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Maternal cocaine abuse may increase the incidence of perinatal asphyxia. In nonexposed asphyxiated neonates, decreased cerebrospinal fluid (CSF) cAMP concentrations are associated with poor neurological outcome. On the other hand, cocaine increases central nervous system (CNS) cAMP. Therefore, we hypothesized that in utero cocaine exposure may increase brain cAMP and thereby preserve cerebrovascular responses to cAMP-dependent stimuli following asphyxia. Pregnant pigs received either cocaine (1 mg/kg, i.v.) twice weekly during the last trimester or normal saline vehicle (sham-control) and were allowed to deliver vaginally at term. Cranial windows were implanted in the newborn pigs within the first week of life and used to collect CSF for cAMP determinations and to assess changes in pial arteriolar diameters (PAD). In the first part of the study, pial arteriolar responses to different vasodilator and vasoconstrictor stimuli were evaluated in piglets prior to asphyxia (n = 20). In newborn pigs exposed to cocaine, cerebrovascular responses to hypercapnia and norepinephrine were significantly exaggerated compared to controls. Then, piglets were randomly selected for the second part of the study that involved prolonged asphyxia (n = 12). In cocaine-exposed but not sham-control piglets, CSF cAMP increased markedly during asphyxia. In the sham piglets, but not the cocaine-exposed piglets, CSF cAMP fell progressively below the baseline during recovery. Cerebrovascular reactivity to cAMP-dependent stimuli (hypercapnia and isoproterenol) was preserved during recovery from asphyxia in the cocaine-exposed piglets but significantly attenuated in the sham controls. We conclude that piglets with chronic prenatal exposure to cocaine show exaggerated cerebrovascular responses to vasogenic stimuli and preserved cAMP-dependent cerebral vasoreactivity following asphyxia.
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Affiliation(s)
- Massroor Pourcyrous
- Laboratory for Research in Neonatal Physiology, Department of Pediatrics, The University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA.
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Abstract
Hypnic headache syndrome is a benign, recurrent, late-onset headache disorder that occurs exclusively during sleep. Lithium has been reported to be an effective treatment, but the side effects of this medication are sometimes prohibitive, particularly in the elderly. Other drugs have been reported to be effective in this disorder, including caffeine, flunarizine, and verapamil. Recently, indomethacin has been reported to effectively suppress hypnic headaches. We report the response of seven patients with hypnic headache who were treated with indomethacin. Hypnic headache syndrome appears to represent yet another headache disorder in which there is sometimes an impressive response to indomethacin.
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Affiliation(s)
- D W Dodick
- Department of Neurology, Mayo Clinic, Scottsdale, AR 85259, USA
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Dodick DW, Jones JM, Capobianco DJ. Hypnic Headache: Another Indomethacin‐Responsive Headache Syndrome? Headache 2000. [DOI: 10.1111/j.1526-4610.2000.00150.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- David W. Dodick
- From the Departments of Neurology, Mayo Clinic, Scottsdale, Ariz
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Fang X, Moore SA, Stoll LL, Rich G, Kaduce TL, Weintraub NL, Spector AA. 14,15-Epoxyeicosatrienoic acid inhibits prostaglandin E2 production in vascular smooth muscle cells. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 275:H2113-21. [PMID: 9843811 DOI: 10.1152/ajpheart.1998.275.6.h2113] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
14,15-Epoxyeicosatrienoic acid (EET), a cytochrome P-450 epoxygenase product of arachidonic acid (AA), reduced PGE2 formation by 40-75% in porcine aortic and murine brain microvascular smooth muscle cells. The inhibition was reversed 6-10 h after removal of 14,15-EET from the medium and was regioisomeric specific; 8,9-EET produced a smaller effect, whereas 11,12- and 5,6-EET were ineffective. Although the cells converted 14,15-EET to 14, 15-dihydroxyeicosatrienoic acid (14,15-DHET), 14,15-DHET did not inhibit PGE2 formation, and the 14,15-EET-induced inhibition was potentiated by 4-phenylchalcone oxide, an epoxide hydrolase inhibitor. The inhibition occurred when substrate amounts of AA were used and was not accompanied by enhanced production of other PGs, suggesting an effect on PGH synthase; however, in murine cells, 14, 15-EET did not reduce PGH synthase mRNA or protein. Moreover, the 14, 15-EET-induced decrease in PGE2 production was overcome by increasing the concentration of AA, but not oleic acid (which is not a substrate for PGH synthase). These findings suggest that 14,15-EET competitively inhibits PGH synthase activity in vascular smooth muscle cells. The 14,15-EET-induced inhibition of PGE2 production resulted in potentiation of platelet-derived growth factor-induced smooth muscle cell proliferation, suggesting that the competitive inhibition of PGH synthase by 14,15-EET can affect growth responses in smooth muscle cells.
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MESH Headings
- 8,11,14-Eicosatrienoic Acid/analogs & derivatives
- 8,11,14-Eicosatrienoic Acid/pharmacology
- Animals
- Aorta/cytology
- Aorta/drug effects
- Aorta/metabolism
- Cell Division/drug effects
- Cells, Cultured
- Cerebrovascular Circulation/physiology
- Dinoprostone/antagonists & inhibitors
- Hydroxyeicosatetraenoic Acids/pharmacology
- Microcirculation/physiology
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Platelet-Derived Growth Factor/pharmacology
- Swine
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Affiliation(s)
- X Fang
- Department of Biochemistry, College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA
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Hamada M, Ogura Y, Miyamoto K, Nishiwaki H, Hiroshiba N, Honda Y. Retinal leukocyte behavior in experimental autoimmune uveoretinitis of rats. Exp Eye Res 1997; 65:445-50. [PMID: 9299181 DOI: 10.1006/exer.1997.0361] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In vivo retinal leukocyte behavior in the experimental autoimmune uveoretinitis (EAU) of rats was investigated using acridine orange digital fluorography. The technique employed high resolution images obtained from a scanning laser ophthalmoscope (SLO) subsequent to staining with the fluorescent nuclear dye, acridine orange. Two weeks after immunization with synthetic peptides of retinal soluble antigen (S-Ag), acridine orange was intravenously injected, and fundus images were generated by SLO. Many rolling leukocytes were observed along the venous walls as slowly moving fluorescent dots; moreover, leukocytes infiltrating into the vitreous cavity were also noted especially over the retinal veins, but not over the retinal arteries. In addition, major retinal vessels were significantly dilated. The diameters of the retinal veins at a distance of 1 disc diameter away from the center of the optic disc were 49.8+/-4.5 micron for the normal rats and 88.2+/-3.6 micron for the EAU rats, respectively (P<0.001). Similarly, the diameters of retinal arteries were 32.6+/-3.7 micron for the normal rats, 53.8+/-1.5 micron for the EAU rats, respectively (P<0.01). The dilation was more prominent in the veins than in the arteries. These results suggest that it is possible to visualize the retinal involvement of EAU in vivo. The results also suggest that leukocyte-endothelial interaction and extravascular infiltration in the retinal venous vasculature may play significant roles in the early stages of posterior segment inflammation in EAU.
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Affiliation(s)
- M Hamada
- Department of Ophthalmology and Visual Sciences,, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Peredo HA, Feleder EC, Adler-Graschinsky E. Differential effects of acetylcholine and bradykinin on prostanoid release from the rat mesenteric bed: role of endothelium and of nitric oxide. Prostaglandins Leukot Essent Fatty Acids 1997; 56:253-8. [PMID: 9150369 DOI: 10.1016/s0952-3278(97)90567-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The roles of nitric oxide and of endothelium in the effects of the vasorelaxing agents acetylcholine and bradykinin on the production of prostanoids was studied in the isolated and perfused mesenteric vascular bed of the rat. Prostanoids were measured in the perfusate by high-performance liquid chromatography (HPLC). In the intact vascular bed, 1 microM bradykinin increased the release of 6-keto-prostaglandinF(1alpha) (stable metabolite of prostacyclin) and of prostaglandin E2 and 10 microM acetylcholine stimulated the efflux of prostacyclin only. In the de-endothelialized vascular bed, bradykinin increased the release of prostacyclin whereas acetylcholine increased the efflux of thromboxane. The inhibition of nitric oxide synthesis with 100 microM N(G)-nitro-L-arginine methyl ester prevented the effect of bradykinin but did not modify the effects of acetylcholine on prostanoid release. In addition, 100 microM L-arginine reversed the inhibitory effect of N(G)-nitro L-arginine methyl ester on bradykinin-stimulated prostaglandin production. It is concluded that acetylcholine and bradykinin stimulate prostanoid release in the rat mesenteric vascular bed with different patterns and through different mechanisms.
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Affiliation(s)
- H A Peredo
- Instituto de Investigaciones Farmacológicas (ININFA, CONICET), Buenos Aires, Argentina
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Bari F, Louis TM, Meng W, Busija DW. Global ischemia impairs ATP-sensitive K+ channel function in cerebral arterioles in piglets. Stroke 1996; 27:1874-80; discussion 1880-1. [PMID: 8841347 DOI: 10.1161/01.str.27.10.1874] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
BACKGROUND AND PURPOSE Indirect evidence from studies in which calcitonin gene-related peptide was used indicates that anoxic stress suppresses functioning of cerebral vascular ATP-sensitive K+ channels. The purpose of this study was to directly examine effects of total global ischemia on cerebral arteriolar dilator responses to activators of ATP-sensitive K+ channels. METHODS We measured pial arteriolar diameters in anesthetized piglets using a closed cranial window and intravital microscopy. Baseline diameters were approximately 100 microns. Arteriolar responses to aprikalim (10(-8) and 10(-6) mol/L), a pharmacological activator of ATP-sensitive K+ channels, and iloprost (0.1 and 1 microgram/mL), a physiological activator of these channels, were determined before and 1, 2, and 4 hours after a 10-minute period of total global ischemia. Ischemia was caused by increasing intracranial pressure. RESULTS Before ischemia, aprikalim dilated cerebral arterioles by 7 +/- 2% at 10(-8) mol/L and by 25 +/- 4% at 10(-6) mol/L (n = 5). At 1 hour after ischemia, aprikalim did not cause significant dilation at either dose (3 +/- 2% at 10(-8) mol/L and 7 +/- 4% at 10(-6) mol/L; P < .05 compared with corresponding preischemic response). Arteriolar dilation returned toward normal values at 2 and 4 hours. Similar results were found with iloprost. Furthermore, prior treatment with indomethacin (5 mg/kg) preserved normal arteriolar dilation to aprikalim and iloprost after ischemia. In contrast, arteriolar dilator responses to prostaglandin E2 were intact after ischemia. CONCLUSIONS Ischemia transiently eliminates cerebral arteriolar dilation to activation of ATP-sensitive K+ channels; arteriolar responses are suppressed at 1 hour and return toward normal over 2 to 4 hours. In addition, reduced responsiveness can be prevented by prior treatment with indomethacin.
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Affiliation(s)
- F Bari
- Department of Physiology and Pharmacology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157-1083, USA
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