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Shah KA, White TG, Powell K, Woo HH, Narayan RK, Li C. Trigeminal Nerve Stimulation Improves Cerebral Macrocirculation and Microcirculation After Subarachnoid Hemorrhage: An Exploratory Study. Neurosurgery 2022; 90:485-494. [PMID: 35188109 PMCID: PMC9514749 DOI: 10.1227/neu.0000000000001854] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 11/14/2021] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Delayed cerebral ischemia (DCI) is the most consequential secondary insult after aneurysmal subarachnoid hemorrhage (SAH). It is a multifactorial process caused by a combination of large artery vasospasm and microcirculatory dysregulation. Despite numerous efforts, no effective therapeutic strategies are available to prevent DCI. The trigeminal nerve richly innervates cerebral blood vessels and releases a host of vasoactive agents upon stimulation. As such, electrical trigeminal nerve stimulation (TNS) has the capability of enhancing cerebral circulation. OBJECTIVE To determine whether TNS can restore impaired cerebral macrocirculation and microcirculation in an experimental rat model of SAH. METHODS The animals were randomly assigned to sham-operated, SAH-control, and SAH-TNS groups. SAH was induced by endovascular perforation on Day 0, followed by KCl-induced cortical spreading depolarization on day 1, and sample collection on day 2. TNS was delivered on day 1. Multiple end points were assessed including cerebral vasospasm, microvascular spasm, microthrombosis, calcitonin gene-related peptide and intercellular adhesion molecule-1 concentrations, degree of cerebral ischemia and apoptosis, and neurobehavioral outcomes. RESULTS SAH resulted in significant vasoconstriction in both major cerebral vessels and cortical pial arterioles. Compared with the SAH-control group, TNS increased lumen diameters of the internal carotid artery, middle cerebral artery, and anterior cerebral artery, and decreased pial arteriolar wall thickness. Additionally, TNS increased cerebrospinal fluid calcitonin gene-related peptide levels, and decreased cortical intercellular adhesion molecule-1 expression, parenchymal microthrombi formation, ischemia-induced hypoxic injury, cellular apoptosis, and neurobehavioral deficits. CONCLUSION Our results suggest that TNS can enhance cerebral circulation at multiple levels, lessen the impact of cerebral ischemia, and ameliorate the consequences of DCI after SAH.
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Affiliation(s)
- Kevin A. Shah
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA;
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Timothy G. White
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Keren Powell
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA;
| | - Henry H. Woo
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Raj K. Narayan
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA;
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Chunyan Li
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA;
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
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Li C, White TG, Shah KA, Chaung W, Powell K, Wang P, Woo HH, Narayan RK. Percutaneous Trigeminal Nerve Stimulation Induces Cerebral Vasodilation in a Dose-Dependent Manner. Neurosurgery 2021; 88:E529-E536. [PMID: 33677599 DOI: 10.1093/neuros/nyab053] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/26/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The trigeminal nerve directly innervates key vascular structures both centrally and peripherally. Centrally, it is known to innervate the brainstem and cavernous sinus, whereas peripherally the trigemino-cerebrovascular network innervates the majority of the cerebral vasculature. Upon stimulation, it permits direct modulation of cerebral blood flow (CBF), making the trigeminal nerve a promising target for the management of cerebral vasospasm. However, trigeminally mediated cerebral vasodilation has not been applied to the treatment of vasospasm. OBJECTIVE To determine the effect of percutaneous electrical stimulation of the infraorbital branch of the trigeminal nerve (pTNS) on the cerebral vasculature. METHODS In order to determine the stimulus-response function of pTNS on cerebral vasodilation, CBF, arterial blood pressure, cerebrovascular resistance, intracranial pressure, cerebral perfusion pressure, cerebrospinal fluid calcitonin gene-related peptide (CGRP) concentrations, and the diameter of cerebral vessels were measured in healthy and subarachnoid hemorrhage (SAH) rats. RESULTS The present study demonstrates, for the first time, that pTNS increases brain CGRP concentrations in a dose-dependent manner, thereby producing controllable cerebral vasodilation. This vasodilatory response appears to be independent of the pressor response induced by pTNS, as it is maintained even after transection of the spinal cord at the C5-C6 level and shown to be confined to the infraorbital nerve by administration of lidocaine or destroying it. Furthermore, such pTNS-induced vasodilatory response of cerebral vessels is retained after SAH-induced vasospasm. CONCLUSION Our study demonstrates that pTNS is a promising vasodilator and increases CBF, cerebral perfusion, and CGRP concentration both in normal and vasoconstrictive conditions.
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Affiliation(s)
- Chunyan Li
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA.,Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Timothy G White
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Kevin A Shah
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Wayne Chaung
- Center for Immunology and Inflammation, The Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Keren Powell
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Ping Wang
- Center for Immunology and Inflammation, The Feinstein Institutes for Medical Research, Manhasset, New York, USA
| | - Henry H Woo
- Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
| | - Raj K Narayan
- Translational Brain Research Laboratory, The Feinstein Institutes for Medical Research, Manhasset, New York, USA.,Department of Neurosurgery, Zucker School of Medicine at Hofstra/Northwell, Hempstead, New York, USA
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Leptin attenuates cerebral ischemia/reperfusion injury partially by CGRP expression. Eur J Pharmacol 2011; 671:61-9. [DOI: 10.1016/j.ejphar.2011.09.170] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Revised: 09/14/2011] [Accepted: 09/15/2011] [Indexed: 01/08/2023]
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Calcitonin gene-related peptide enhances CREB phosphorylation and attenuates tau protein phosphorylation in rat brain during focal cerebral ischemia/reperfusion. Biomed Pharmacother 2009; 64:430-6. [PMID: 20537498 DOI: 10.1016/j.biopha.2009.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2009] [Accepted: 06/07/2009] [Indexed: 01/09/2023] Open
Abstract
Calcitonin gene-related peptide (CGRP) is a potent vasodilator and immune cell modulator. Exogenous CGRP could increase the cerebral blood flow significantly and protect the ischemic neurons, but its mechanism is not entirely clear. The effect of CGRP on the expressions of CREB and tau in the ipsilateral parietal cortex were detected in focal cerebral ischemia/reperfusion model. The expression of CREB mRNA decreased in ischemia/reperfusion group (I/R group) compared with that of the sham operation group, and it got highest in CGRP group. CREB expression was lesser in I/R group than sham group, but it became more in CGRP group than I/R group. Phospho-CREB became more in I/R group, and it got most in CGRP group in the cortex. No significant difference was observed on Tau mRNA expression in all the groups. The level of tau hyperphosphorylation at Ser199/202 site and total tau in rat parietal cortex were significantly higher in I/R group than sham group. CGRP significantly inhibited tau hyperphosphorylation and the level of total tau also significantly reduced in CGRP group than that in I/R group. CGRP can upregulate the expression of CREB and phospho-CREB and attenuate the level of tau hyperphosphorylation in the ischemic neurons of the parietal cortex during focal cerebral ischemia/reperfusion. Phosphorylating CREB and inhibiting tau phosphorylation are probably involved in the mechanism of protective effect of CGRP to ischemic neurons.
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Kis B, Abrahám CS, Deli MA, Kobayashi H, Niwa M, Yamashita H, Busija DW, Ueta Y. Adrenomedullin, an autocrine mediator of blood-brain barrier function. Hypertens Res 2003; 26 Suppl:S61-70. [PMID: 12630813 DOI: 10.1291/hypres.26.s61] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Since the discovery that adrenomedullin gene expression is 20- to 40-fold higher in endothelial cells than even in the adrenal medulla, this peptide has been regarded as an important secretory product of the vascular endothelium, together with nitric oxide, eicosanoids, endothelin-1, and other vasoactive metabolites. Cerebral endothelial cells secrete an exceptionally large amount of adrenomedullin, and the adrenomedullin concentration is about 50% higher in the cerebral circulation than in the peripheral vasculature. The adrenomedullin production of cerebral endothelial cells is induced by astrocyte-derived factors. Adrenomedullin causes vasodilation in the cerebral circulation, may participate in the maintenance of the resting cerebral blood flow, and may be protective against ischemic brain injury. Recent data from our laboratory indicate that adrenomedullin, as an endothelium-derived autocrine/paracrine hormone, plays an important role in the regulation of specific blood-brain barrier properties. Adrenomedullin is suggested to be one of the physiological links between astrocyte-derived factors, cyclic adenosine 3'5'-monophosphate (cAMP), and the induction and maintenance of the blood-brain barrier. Moreover, the role of adrenomedullin in the differentiation and proliferation of endothelial cells and in angiogenesis suggests a more complex function for adrenomedullin in the cerebral circulation and in the development of the blood-brain barrier.
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Affiliation(s)
- Béla Kis
- Department of Physiology and Pharmacology, Wake Forest University, Medical Center Boulevard, Winston-Salem, NC 27157, USA.
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Béla K, Csongor AS, Deli MA, Ueta Y. Adrenomedullin and migraine. Headache 2002; 42:1064-5. [PMID: 12453043 DOI: 10.1046/j.1526-4610.2002.02241.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Oliver KR, Wainwright A, Edvinsson L, Pickard JD, Hill RG. Immunohistochemical localization of calcitonin receptor-like receptor and receptor activity-modifying proteins in the human cerebral vasculature. J Cereb Blood Flow Metab 2002; 22:620-9. [PMID: 11973435 DOI: 10.1097/00004647-200205000-00014] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Calcitonin gene-related peptide and adrenomedullin belong to a structurally related neuropeptide family and are potent vasodilators expressed in the trigeminovascular system. The molecular identity of receptors for these proteins has only recently been elucidated. Central to functional binding of these neuropeptides is the G-protein-coupled receptor, the calcitonin receptor-like receptor (CRLR), whose cell surface expression and pharmacology is determined by coexpression of a receptor activity-modifying protein (RAMP). CRLR combined with RAMP binds calcitonin gene-related peptide with high affinity, whereas CRLR coexpression with RAMP2 or -3 confers high-affinity binding of adrenomedullin. The authors investigated the expression of these receptor components in human cerebral vasculature to further characterize neuropeptide receptor content and the potential functions of these receptors. Localization has been carried out using specific antisera raised against immunogenic peptide sequences that were subsequently applied using modern immunohistochemical techniques and confocal microscopy. The results are the first to show the presence of these receptor component proteins in human middle meningeal, middle cerebral, pial, and superficial temporal vessels, and confirm that both calcitonin gene-related peptide and adrenomedullin receptors may arise from the coassembly of RAMPs with CRLR in these vessel types. These novel data advance the understanding of the molecular function of the trigeminovascular system, its potential role in vascular headache disorders such as migraine, and may lead to possible ways in which future synthetic ligands may be applied to manage these disorders.
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Affiliation(s)
- Kevin R Oliver
- The Neuroscience Research Center, Merck, Sharp and Dohme Research Laboratories, Terling's Park, Harlow, Essex CM20 2QR, United Kingdom.
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Moreno MJ, Terrón JA, Stanimirovic DB, Doods H, Hamel E. Characterization of calcitonin gene-related peptide (CGRP) receptors and their receptor-activity-modifying proteins (RAMPs) in human brain microvascular and astroglial cells in culture. Neuropharmacology 2002; 42:270-80. [PMID: 11804624 DOI: 10.1016/s0028-3908(01)00176-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
1. In the present study, we examined the expression of the CGRP receptor-activity-modifying proteins (RAMP1, RAMP2 and RAMP3) and receptor component protein (RCP) in human brain astrocytes (AST), cerebromicrovascular endothelial (EC) and smooth muscle (SMC) cells in culture. Further, we pharmacologically characterized CGRP receptors in these cells by assessing the potency of the CGRP receptor antagonists h-alpha CGRP(8-37) and the new non-peptide compound BIBN4096BS to block the production of cAMP elicited by CGRP(1) and CGRP(2) receptor agonists. 2. AST, EC and SMC all expressed mRNAs for RAMP1, RAMP2 and RCP. In contrast, message for RAMP3 was detected in AST, but not in SMC and in only one out of four preparations of EC. 3. h-alpha CGRP, h-beta CGRP and [Cys (Et)(2,7)]-h-alpha CGRP exerted concentration-dependent production of cAMP in all cultures, with a maximal effect at 25-50 nM (20-60-fold increase from basal levels). In contrast, 50 nM [Cys (Acm)(2,7)]-h-alpha CGRP only induced a weak stimulatory effect on cAMP formation, especially in SMC and AST (1.5- and 5-fold increase above baseline, respectively). 4. h-alpha CGRP(8-37) and BIBN4096BS concentration-dependently inhibited cAMP formation evoked by CGRP receptor agonists. Depending on the agonists used, h-alpha CGRP(8-37) distinguished two different CGRP receptors for which it exhibited low (pIC(50)< or =6.4) and high (pIC(50) approximately 7.3) affinity, respectively. BIBN4096BS was much more potent (>2.5 orders of magnitude) than h-alpha CGRP(8-37). Further, BIBN4096BS was able to discriminate three different CGRP receptor sites for which it exhibited low (pIC(50) approximately 9.3-9.9), intermediate (pIC(50) approximately 10.9), and a very high (pIC(50) approximately 13.7) affinity, respectively. Together, these results suggest the presence of CGRP(1) and/or CGRP(2) receptors in human brain AST, EC and SMC, and of an additional population of CGRP receptors in AST, possibly associated to the combined expression of RAMP3 and RCP in these cells, for which BIBN4096BS exhibits an exquisitely high affinity.
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Affiliation(s)
- Mariá Jesús Moreno
- Laboratory of Cerebrovascular Research, Department of Neurology and Neurosurgery, Montreal Neurological Institute, 3801 University Street, Montréal, QC, Canada H3A 2B4
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Kis B, Abrahám CS, Deli MA, Kobayashi H, Wada A, Niwa M, Yamashita H, Ueta Y. Adrenomedullin in the cerebral circulation. Peptides 2001; 22:1825-34. [PMID: 11754969 DOI: 10.1016/s0196-9781(01)00533-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The central nervous system requires an effective autoregulation of cerebral circulation in order to meet the critical and unusual demands of the brain. In addition, cerebral microvessels has a unique feature, the formation of the blood-brain barrier, which contributes to the stability of the brain parenchymal microenvironment. Many factors are known to be involved in the regulation of cerebral circulation and blood-brain barrier functions. In the last few years a new potential candidate, adrenomedullin, a hypotensive peptide was added to this list. Adrenomedullin has a potent vasodilator effect on the cerebral vasculature, and it may be implicated in the pathologic mechanism of cerebrovascular diseases. In this review, we describe current knowledge about the origin and possible role of adrenomedullin in the regulation of cerebral circulation and blood-brain barrier functions.
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Affiliation(s)
- B Kis
- Department of Physiology, University of Occupational and Environmental Health, 807-8555, Kitakyushu, Japan.
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Moreno MJ, Cohen Z, Stanimirovic DB, Hamel E. Functional calcitonin gene-related peptide type 1 and adrenomedullin receptors in human trigeminal ganglia, brain vessels, and cerebromicrovascular or astroglial cells in culture. J Cereb Blood Flow Metab 1999; 19:1270-8. [PMID: 10566974 DOI: 10.1097/00004647-199911000-00012] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Calcitonin gene-related peptide (CGRP) and adrenomedullin (ADM) are potent dilators of human brain arteries, and they have been implicated in the neurogenic inflammation underlying migraine headache and in the evolution of stroke, respectively. However, little is known about the presynaptic and postsynaptic distribution of their respective receptors in the human cerebrovascular bed and trigeminovascular system. In the current study, the expression of mRNA for ADM and the two cloned human CGRP1 receptors (identified here as A-CGRP1 receptors [Aiyar et al., 1996] and K-CGRP1 receptors) [Kapas and Clark, 1995] were evaluated in human brain vessels and trigeminal ganglia. Further, the ability of CGRP and ADM to activate adenylate cyclase in cerebromicrovascular and astroglial cell cultures was determined, and the receptors involved were characterized pharmacologically. Isolated human pial vessels, intracortical microvessels, and capillaries, as well as cultures of brain endothelial (EC), smooth muscle (SMC), and astroglial (AST) cells, all expressed mRNA for the two cloned CGRP1 receptors; however, message for the K-CGRP1 receptor was barely detectable in microvascular tissues and cells. In contrast, only isolated capillaries and cultured AST exhibited message for the ADM receptor. In human trigeminal ganglia, mRNA for ADM and the two CGRP1 receptors was systematically present. The CGRP dose-dependently increased (up to 50-fold) cAMP formation in cell cultures, an effect significantly blocked by 0.1 to 10 micromol/L of the CGRP1 receptor antagonist CGRP8-37. The ADM receptor agonist, ADM13-52 (1 micromol/L), similarly increased cAMP production in all cell types, and this response was virtually abolished by 1 micromol/L CGRP8-37. Low concentrations (1 to 10 micromol/L) of the ADM receptor antagonist ADM22-52 blocked the ADM13-52-induced cAMP formation in AST (26% at 10 micromol/L, P < 0.05), whereas they potentiated this response in brain EC and SMC (40% and 100%, P < 0.001, respectively). Even at a higher dose (50 micromol/L), ADM22-52 inhibited the ADM13-52 effect in vascular cells (45%) much less effectively than in AST (95%). These results indicate that both CGRP and ADM can affect human brain vessels through a CGRP1 receptor, and they further suggest the presence of functional ADM receptors in human astroglial cells.
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Affiliation(s)
- M J Moreno
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, Québec, Canada
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Takao M, Tomita M, Tanahashi N, Kobari M, Fukuuchi Y. Transient vasodilatory effects of adrenomedullin on cerebral parenchymal microvessels in cats. Neurosci Lett 1999; 268:147-50. [PMID: 10406026 DOI: 10.1016/s0304-3940(99)00408-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We studied the effects of adrenomedullin, structural homology of calcitonin gene-related peptide (CGRP), on the cerebral parenchymal microvessels in cats by our photoelectric method. Adrenomedullin significantly increased cerebral blood volume (CBV) at 0.5 and 1 min after intracarotid injection (0.01-1 nmol/kg, maximum; +0.71 vol% for 0.1 nmol/kg adrenomedullin). Adrenomedullin antagonist, adrenomedullin22-62 (0.01-10 nmol/kg), caused no significant changes in CBV and mean arterial blood pressure. Preinjection of 10 nmol/kg adrenomedullin22-52 blocked the vasodilatory effect of 0.01 nmol/kg adrenomedullin (P < 0.05). Pretreatment of 1 nmol/kg CGRP8-37, which has antagonistic activity against CGRP, also inhibited the vasodilatation of adrenomedullin. The degree of CBV reduction after adrenomedullin22-52 injection was greater than that after CGRP8-37 injection. Adrenomedullin has no major role in the maintenance of resting tone of intracerebral parenchymal vessels. Intravascularly administered adrenomedullin dilates cortical microvessels mainly through the specific adrenomedullin receptor.
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Affiliation(s)
- M Takao
- Department of Neurology, School of Medicine, Keio University, Tokyo, Japan.
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Hull KL, Fathimani K, Sharma P, Harvey S. Calcitropic peptides: neural perspectives. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. PART C, PHARMACOLOGY, TOXICOLOGY & ENDOCRINOLOGY 1998; 119:389-410. [PMID: 9827010 DOI: 10.1016/s0742-8413(98)00010-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In mammals and higher vertebrates, calcitropic peptides are produced by peripheral endocrine glands: the parathyroid gland (PTH), thyroid or ultimobranchial gland (calcitonin) and the anterior pituitary gland (growth hormone and prolactin). These hormones are, however, also found in the neural tissues of lower vertebrates and invertebrates that lack these endocrine organs, suggesting that neural tissue may be an ancestral site of calcitropic peptide synthesis. Indeed, the demonstration of CNS receptors for these calcitropic peptides and their induction of neurological actions suggest that these hormones arose as neuropeptides. Neural and neuroendocrine roles of some of these calcitropic hormones (calcitonin and parathyroid hormone) and related peptides (calcitonin gene related peptide, stanniocalcin and parathyroid hormone related peptide) are thus the focus of this review.
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Affiliation(s)
- K L Hull
- Department of Physiology, University of Alberta, Edmonton, Canada
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Kobari M, Tomita M, Tanahashi N, Yokoyama M, Takao M, Fukuuchi Y. Intravascular substance P dilates cerebral parenchymal vessels through a specific tachykinin NK1 receptor in cats. Eur J Pharmacol 1996; 317:269-74. [PMID: 8997610 DOI: 10.1016/s0014-2999(96)00725-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The role of substance P in the cerebral parenchymal circulation was examined in 19 anesthetized cats. The local cerebral blood volume in the temporoparietal cortex was measured by our photoelectric method. Cerebral blood volume reflects the cumulative dimensions of the parenchymal microvessels. Intravenous injection of 0.01, 0.1, and 1 mg/kg FK888 (N2-[(4R)-4-hydroxy-1-(1-methyl-1H-indol-3-yl) carbonyl-L-prolyl]-N-methyl-N-phenylmethyl-3-(2-naphthyl)-L-alaninamide) , a selective tachykinin NK1 receptor antagonist, had no significant effects (compared to the vehicle, ethanol) on cerebral blood volume and mean arterial blood pressure. Intracarotid injection of 1, 10, 100 pmol/kg, and 1 nmol/kg substance P increased cerebral blood volume (P < 0.01) in a dose-dependent manner (maximal increase of 6.5% at 5 min). Following injection of 1 nmol/kg substance P, cerebral blood volume was initially reduced, possibly due to the marked fall in mean arterial blood pressure (P < 0.01). The cerebral blood volume increase elicited by 1 nmol/kg substance P was strongly blocked (P < 0.05) by prior injection of 1 mg/kg FK888. However, the depressor effect of 1 nmol/kg substance P (-24 +/- 4 mm Hg at 30 s, P < 0.01) was partially inhibited (P < 0.01) by FK888. We conclude that endogenous substance P may not have a significant role in the maintenance of resting tone of cerebral parenchymal vessels. Intravascular substance P, however, dilates the small microvessels through a specific tachykinin NK1 receptor and could be involved in the development of pathologic processes such as migraine headache.
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Affiliation(s)
- M Kobari
- Department of Neurology, School of Medicine, Keio University, Tokyo, Japan
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