1.
Ahnstedt, Hilda, et al.
(författare)
Human cerebrovascular contractile receptors are upregulated via a B-Raf/MEK/ERK-sensitive signaling pathway.
2011
Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 12
Tidskriftsartikel (refereegranskat) abstract
ABSTRACT: BACKGROUND: Cerebral ischemia results in a rapid increase in contractile cerebrovascular receptors, such as the 5-hydroxytryptamine type 1B (5-HT1B), angiotensin II type 1 (AT1), and endothelin type B (ETB) receptors, in the vessel walls within the ischemic region, which further impairs local blood flow and aggravates tissue damage. This receptor upregulation occurs via activation of the mitogen-activated protein kinase pathway. We therefore hypothesized an important role for B-Raf, the first signaling molecule in the pathway. To test our hypothesis, human cerebral arteries were incubated at 37°C for 48 h in the absence or presence of a B-Raf inhibitor: SB-386023 or SB-590885. Contractile properties were evaluated in a myograph and protein expression of the individual receptors and activated phosphorylated B-Raf (p-B-Raf) was evaluated immunohistochemically. RESULTS: 5-HT1B, AT1, and ETB receptor-mediated contractions were significantly reduced by application of SB-590885, and to a smaller extent by SB-386023. A marked reduction in AT1 receptor immunoreactivity was observed after treatment with SB-590885. Treatment with SB-590885 and SB-386023 diminished the culture-induced increase of p-B-Raf immunoreactivity. CONCLUSIONS: B-Raf signaling has a key function in the altered expression of vascular contractile receptors observed after organ culture. Therefore, specific targeting of B-Raf might be a novel approach to reduce tissue damage after cerebral ischemia by preventing the previously observed upregulation of contractile receptors in smooth muscle cells.
2.
Ansar, Saema, et al.
(författare)
Inhibition of cerebrovascular raf activation attenuates cerebral blood flow and prevents upregulation of contractile receptors after subarachnoid hemorrhage
2011
Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 12
Tidskriftsartikel (refereegranskat) abstract
Background: Late cerebral ischemia carries high morbidity and mortality after subarachnoid hemorrhage (SAH) due to reduced cerebral blood flow (CBF) and the subsequent cerebral ischemia which is associated with upregulation of contractile receptors in the vascular smooth muscle cells (SMC) via activation of mitogen-activated protein kinase (MAPK) of the extracellular signal-regulated kinase (ERK)1/2 signal pathway. We hypothesize that SAH initiates cerebrovascular ERK1/2 activation, resulting in receptor upregulation. The raf inhibitor will inhibit the molecular events upstream ERK1/2 and may provide a therapeutic window for treatment of cerebral ischemia after SAH. Results: Here we demonstrate that SAH increases the phosphorylation level of ERK1/2 in cerebral vessels and reduces the neurology score in rats in additional with the CBF measured by an autoradiographic method. The intracisternal administration of SB-386023-b, a specific inhibitor of raf, given 6 h after SAH, aborts the receptor changes and protects the brain from the development of late cerebral ischemia at 48 h. This is accompanied by reduced phosphorylation of ERK1/2 in cerebrovascular SMC. SAH per se enhances contractile responses to endothelin-1 (ET-1), 5-carboxamidotryptamine (5-CT) and angiotensin II (Ang II), upregulates ETB, 5-HT1B and AT(1) receptor mRNA and protein levels. Treatment with SB-386023-b given as late as at 6 h but not at 12 h after the SAH significantly decreased the receptor upregulation, the reduction in CBF and the neurology score. Conclusion: These results provide evidence for a role of the ERK1/2 pathway in regulation of expression of cerebrovascular SMC receptors. It is suggested that raf inhibition may reduce late cerebral ischemia after SAH and provides a realistic time window for therapy.
3.
Ansar, Saema, et al.
(författare)
MAPK signaling pathway regulates cerebrovascular receptor expression in human cerebral arteries
2013
Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 14
Tidskriftsartikel (refereegranskat) abstract
Background: Cerebral ischemia results in enhanced expression of contractile cerebrovascular receptors, such as endothelin type B (ETB), 5-hydroxytryptamine type 1B (5-HT1B), angiotensin II type 1 (AT(1)) and thromboxane (TP) receptors in the cerebral arteries within the ischemic area. The receptor upregulation occurs via activation of the mitogen-activated protein kinases (MAPK) pathway. Previous studies have shown that inhibitors of the MAPK pathway diminished the ischemic area and contractile cerebrovascular receptors after experimental cerebral ischemia. The aim of this study was to examine if the upregulation of contractile cerebrovascular receptors after 48 h of organ culture of human cerebral arteries involves MAPK pathways and if it can be prevented by a MEK1/2 inhibitor. Human cerebral arteries were obtained from patients undergoing intracranial tumor surgery. The vessels were divided into ring segments and incubated for 48 h in the presence or absence of the specific MEK1/2 inhibitor U0126. The vessels were then examined by using in vitro pharmacological methods and protein immunohistochemistry. Results: After organ culture of the cerebral arteries the contractile responses to endothelin (ET)-1, angiotensin (Ang) II and thromboxane (TP) were enhanced in comparison with fresh human arteries. However, 5-carboxamidotryptamine (5-CT) induced decreased contractile responses after organ culture as compared to fresh arteries. Incubation with U0126 diminished the maximum contraction elicited by application of ET-1, Ang II and U46619 in human cerebral arteries. In addition, the MEK1/2 inhibitor decreased the contractile response to 5-CT. Immunohistochemistry revealed that organ culture resulted in increased expression of endothelin ETA, endothelin ETB angiotensin AT(2), 5-hydroxytryptamine 5-HT1B and thromboxane A2 receptors, and elevated levels of activated pERK1/2, all localized to the smooth muscle cells of the cerebral arteries. Co-incubation with U0126 normalized these proteins. Conclusion: The study demonstrated that there is a clear association between human cerebrovascular receptor upregulation via transcription involving activation of the MAPK pathway after organ culture. Inhibition of the MAPK pathways attenuated the vasoconstriction mediated by ET, AT and TP receptors in human cerebral arteries and the enhanced expression of their receptors. The results indicate that MAPK inhibition might be a novel target for treatment of cerebrovascular disorders.
4.
Ansar, Saema, et al.
(författare)
Subarachnoid Hemorrhage Induces Enhanced Expression of Thromboxane A(2) Receptors in Rat Cerebral Arteries.
2010
Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1316, s. 163-172
Tidskriftsartikel (refereegranskat) abstract
Cerebral ischemia remains the key cause of morbidity and mortality after subarachnoid hemorrhage (SAH) with a pathogenesis that is still poorly understood. The aim of the present study was to examine the involvement of thromboxane A(2) receptors (TP) in the patophysiology of cerebral ischemia after SAH in cerebral arteries. SAH was induced in rats by injecting 250 microl blood into the prechiasmatic cistern. Two days after the SAH, cerebral arteries were harvested and contractile responses to the TP receptor agonist U46619 were investigated with myographs. In addition, the contractile responses were examined after pretreatment with selective TP receptor antagonist GR3219b. The TP receptor RNA and protein levels were analyzed by quantitative real-time PCR and immunohistochemistry, respectively. The global and regional cerebral blood flows (CBF) were quantified with an autoradiographic technique. SAH resulted in enhanced contractile responses to U46619 as compared to sham. The TP receptor antagonist GR3219b abolished the enhanced contractile responses to U46619 observed after SAH. The TP receptor mRNA level was elevated after SAH as compared to sham. The level of TP receptor protein on the smooth muscle cells (SMC) was increased in SAH compared to sham, Global and regional CBF was reduced in SAH as compared to sham. The results demonstrate that SAH results in CBF reduction and this is associated with enhanced expression of TP receptors in the SMC of cerebral arteries and microvessels.
5.
Bower, Rebekah L., et al.
(författare)
Mapping the calcitonin receptor in human brain stem
2016
Ingår i: American Journal of Physiology - Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 310:9, s. 788-793
Tidskriftsartikel (refereegranskat) abstract
The calcitonin receptor (CTR) is relevant to three hormonal systems: amylin, calcitonin, and calcitonin gene-related peptide (CGRP). Receptors for amylin and calcitonin are targets for treating obesity, diabetes, and bone disorders. CGRP receptors represent a target for pain and migraine. Amylin receptors (AMY) are a heterodimer formed by the coexpression of CTR with receptor activity-modifying proteins (RAMPs). CTR with RAMP1 responds potently to both amylin and CGRP. The brain stem is a major site of action for circulating amylin and is a rich site of CGRP binding. This study aimed to enhance our understanding of these hormone systems by mapping CTR expression in the human brain stem, specifically the medulla oblongata. Widespread CTR-like immunoreactivity was observed throughout the medulla. Dense CTR staining was noted in several discrete nuclei, including the nucleus of the solitary tract, the hypoglossal nucleus, the cuneate nucleus, spinal trigeminal nucleus, the gracile nucleus, and the inferior olivary nucleus. CTR staining was also observed in the area postrema, the lateral reticular nucleus, and the pyramidal tract. The extensive expression of CTR in the medulla suggests that CTR may be involved in a wider range of functions than currently appreciated.
6.
Cao, Lei, et al.
(författare)
Secondhand smoke exposure induces Raf/ERK/MAPK-mediated upregulation of cerebrovascular endothelin ETA receptors.
2011
Ingår i: BMC Neuroscience. - : Springer Science and Business Media LLC. - 1471-2202. ; 12
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND: Cigarette smoking enhances the risk of stroke. However, the underlying molecular mechanisms are largely unknown. The present study established an in vivo rat secondhand cigarette smoking (SHS) model and examined the hypothesis that SHS upregulates endothelin receptors with increased cerebrovascular contraction via the Raf/extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinases (MAPK) pathway. RESULTS: Rats were exposed to SHS for up to 8 weeks. The cerebral artery vasoconstriction was recorded by a sensitive myograph. The mRNA and protein expressions for endothelin receptors in cerebral arteries were studied by real-time PCR and Western blot. Compared to fresh air exposed rats, cerebral arteries from SHS rats exhibited stronger contractile responses (P < 0.05) mediated by endothelin type A (ETA) receptors. The expressions of mRNA and protein for ETA receptors in the cerebral arteries from SHS rats were higher (P < 0.05) than that in control. SHS did not affect endothelin type B (ETB) receptor-mediated contractions, mRNA or protein levels. The results suggest that SHS upregulates ETA, but not ETB receptors in vivo. After SHS exposure, the mRNA levels of Raf-1 and ERK1/2, the protein expression of phosphorylated (p)-Raf-1 and p-ERK1/2 were increased (P < 0.05). Raf-1 inhibitor, GW5074 suppressed the enhanced ETA receptor-mediated contraction, mRNA and protein levels induced by SHS. In addition, GW5074 inhibited the SHS-caused increased mRNA and phosphorylated protein levels of Raf-1 and ERK1/2, suggesting that SHS induces activation of the Raf/ERK/MAPK pathway. CONCLUSIONS: SHS upregulates cerebrovascular ETA receptors via the Raf/ERK/MAPK pathway, which provides novel understanding of mechanisms involved in SHS-associated stroke.
7.
Christiansen, Isabella Mai, et al.
(författare)
Dual action of the cannabinoid receptor 1 ligand arachidonyl-2′-chloroethylamide on calcitonin gene-related peptide release
2022
Ingår i: Journal of Headache and Pain. - : Springer Science and Business Media LLC. - 1129-2369 .- 1129-2377. ; 23
Tidskriftsartikel (refereegranskat) abstract
Background: Based on the current understanding of the role of neuropeptide signalling in migraine, we explored the therapeutic potential of a specific cannabinoid agonist. The aim of the present study was to examine the effect of the synthetic endocannabinoid (eCB) analogue, arachidonyl-2′-chloroethylamide (ACEA), on calcitonin gene-related peptide (CGRP) release in the dura and trigeminal ganglion (TG), as cannabinoids are known to activate Gi/o-coupled cannabinoid receptors type 1 (CB1), resulting in neuronal inhibition. Methods: The experiments were performed using the hemi-skull model and dissected TGs from male Sprague-Dawley rats. CGRP release was induced by either 60 mM K+ (for depolarization-induced stimulation) or 100 nM capsaicin (for transient receptor potential vanilloid 1 (TRPV1) -induced stimulation) and measured using an enzyme-linked immunosorbent assay. The analysis of CGRP release data was combined with immunohistochemistry in order to study the cellular localization of CB1, cannabinoid receptor type 2 (CB2), CGRP and receptor activity modifying protein 1 (RAMP1), a subunit of the functional CGRP receptor, in the TG. Results: CB1 was predominantly expressed in neuronal somas in which colocalization with CGRP was observed. Furthermore, CB1 exhibited colocalization with RAMP1 in neuronal Aδ-fibres but was not clearly expressed in the CGRP-immunoreactive C-fibres. CB2 was mainly expressed in satellite glial cells and did not show substantial colocalization with either CGRP or RAMP1. Without stimulation, 140 nM ACEA per se caused a significant increase in CGRP release in the dura but not TG, compared to vehicle. Furthermore, 140 nM ACEA did not significantly modify neither K+- nor capsaicin-induced CGRP release. However, when the TRPV1 blocker AMG9810 (1 mM) was coapplied with ACEA, K+-induced CGRP release was significantly attenuated in the TG and dura. Conclusions: Results from the present study indicate that ACEA per se does not exhibit antimigraine potential due to its dual agonistic properties, resulting in activation of both CB1 and TRPV1, and thereby inhibition and stimulation of CGRP release, respectively.
8.
Csati, Anett, et al.
(författare)
Calcitonin gene-related peptide and its receptor components in the human sphenopalatine ganglion - Interaction with the sensory system.
2012
Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1435, s. 29-39
Tidskriftsartikel (refereegranskat) abstract
Clinical studies have suggested a link between the sensory trigeminal system and the parasympathetic ganglia. Calcitonin gene-related peptide (CGRP) is a sensory neuropeptide which plays an important role in vasodilatation and pain transmission in craniocervical structures. The present study was designed to examine if CGRP and CGRP receptor components are present in the human sphenopalatine ganglion (SPG) in order to reveal an interaction between the sensory and parasympathetic systems. Indirect immunofluorescence technique was used for immunohistochemical demonstration of CGRP, the calcitonin receptor-like receptor (CLR) and the receptor activity modifying protein 1 (RAMP1) in human and rat SPG. Cryostat sections were examined and images were obtained using a light- and epifluorescence microscope coupled to a camera to visualize co-labeling by superimposing the digital images. In addition, Western blot technique was used to demonstrate the existence of CGRP receptor components in rat SPG. CGRP immunoreactive fibers were frequently found intraganglionic in the SPG in the vicinity of neurons. CLR immunoreactivity was observed in satellite glial cells (SGCs) as well as in nerve fibers, but not in neurons. RAMP1 immunoreactivity was localized in many neurons and SGCs. Thus, the two CGRP receptor components together were found in the SGCs. In addition, Western blot revealed the presence of RAMP1 and CLR in rat SPG. Our results suggest a possible sensory influence in the parasympathetic cranial ganglia. The sensory CGRP-containing fibers probably originate in the trigeminal ganglion, project to the SPG and act on CGRP receptors on SGCs.
9.
Csati, A, et al.
(författare)
Distribution of vasoactive intestinal peptide, pituitary adenylate cyclase-activating peptide, nitric oxide synthase, and their receptors in human and rat sphenopalatine ganglion.
2012
Ingår i: Neuroscience. - : Elsevier BV. - 1873-7544 .- 0306-4522. ; 202, s. 158-168
Tidskriftsartikel (refereegranskat) abstract
Cranial parasympathetic outflow is mediated through the sphenopalatine ganglion (SPG). The present study was performed to examine the expression of the parasympathetic signaling transmitters and their receptors in human and rat SPG. Indirect immunofluorescence technique was used for the demonstration of vasoactive intestinal peptide (VIP), pituitary adenylate cyclase-activating peptide (PACAP), nitric oxide synthase (NOS), glutamine synthetase (GS), glial fibrillary acidic protein (GFAP), VIP and PACAP common receptors (VPAC1, VPAC2), and PACAP receptor (PAC1). In addition, double labeling was carried out to reveal the co-localization of neurotransmitters. VIP-immunoreactive (-ir) neurons as well as fibers were frequently found in human SPG. Many, homogenously stained NOS-ir cells were found, but no positive fibers. In addition, PACAP-ir was observed in some of the neurons and in fibers. Co-localization was found between VIP and NOS. In rat VIP-, NOS-, and PACAP-ir were found in many neurons and fibers. Co-localization of PACAP and NOS was observed in neurons. PACAP and GS double staining revealed that the PACAP-ir was localized in/close to the cell membrane, but not in the satellite glial cells. PAC1 and VPAC1 immunoreactivity was found in the satellite glial cells of both human and rat. Western blot revealed protein expression of PAC1, VPAC1, and VPAC2 in rat SPG. The trigeminal-autonomic reflex may be active in migraine attacks. We hypothesized that VIP, PACAP, NOS, PAC1, VPAC1, and VPAC2 play a role in the activation of parasympathetic cranial outflow during migraine attacks.
10.
Csáti, A, et al.
(författare)
Kynurenic acid modulates experimentally induced inflammation in the trigeminal ganglion.
2015
Ingår i: Journal of Headache and Pain. - : Springer Science and Business Media LLC. - 1129-2369 .- 1129-2377. ; 16:99
Tidskriftsartikel (refereegranskat) abstract
The trigeminal ganglion (TG) plays a central role in cranial pain. Administration of complete Freund's adjuvant (CFA) into the temporomandibular joint (TMJ) elicits activation of TG. Kynurenic acid (KYNA) is an endogenous excitatory amino acid receptor blocker, which may have an anti-inflammatory effect. We hypothesize that KYNA may reduce CFA-induced activation within the TG.
