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Hove VN, Anderson K, Hayden ER, Pasquariello KZ, Gibson AA, Shen S, Qu J, Jin Y, Miecznikowski JC, Hu S, Sprowl JA. Influence of Tyrosine Kinase Inhibition on OATP1B3-mediated Uptake. Mol Pharmacol 2022; 101:381-389. [PMID: 35383108 DOI: 10.1124/molpharm.121.000287] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 03/22/2022] [Indexed: 11/22/2022] Open
Abstract
The hepatic uptake transporter, OATP1B3, has a broad substrate recognition and plays a significant role in regulating elimination of endogenous biomolecules or xenobiotics via the liver. OATP1B3 works in tandem with OATP1B1, with which it shares approximately 80% sequence homology and a high degree of substrate overlap. Despite some substrates being recognized solely by OATP1B3, its ability to compensate for loss of OATP1B1-mediated elimination, and recognition by regulatory agencies, little is known about OATP1B3 regulatory factors and how they are involved with drug-drug interaction (DDIs). It was recently discovered that OATP1B1 function is mediated by the activity of a particular tyrosine kinase that is sensitive to a variety of tyrosine kinase inhibitors (TKIs). This study reports that OATP1B3 is similarly regulated, as at least 50% of its activity is reduced by 22 FDA approved TKIs. Nilotinib was assessed as the most potent OATP1B3 inhibitor among the investigated TKIs, which can occur at clinically relevant concentrations and acted predominantly through non-competitive inhibition without impacting membrane expression. Finally, OATP1B3 function was determined to be sensitive to the knockdown of LYN, a Src kinase that is sensitive to nilotinib and has been previously implicated in mediating OATP1B1 activity. Collectively, our findings identify tyrosine kinase activity as a major regulator of OATP1B3 function which is sensitive to kinase inhibition. Given that OATP1B1 is similarly regulated, simultaneous disruption of these transporters can have drastic effects on systemic drug concentrations which would promote adverse events. Significance Statement Despite the importance of OATP1B3 as a critical facilitator of hepatic drug elimination, much is unknown of how OATP1B3 activity is mediated, or how such regulators contribute to drug-drug interactions. The current study reports that OATP1B3 activity is dependent on the Src kinase LYN, which is sensitive to numerous tyrosine kinase inhibitors. The findings provide mechanistic insight into the occurrence of many clinical drug-drug interactions, and a rationale for future study of tyrosine kinase activity regulating drug disposition or transport.
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Affiliation(s)
| | | | | | | | | | | | - Jun Qu
- University of Buffalo, United States
| | - Yan Jin
- The Ohio State University, United States
| | | | | | - Jason A Sprowl
- School of Pharmacy, University of Buffalo, United States
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2
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Kayesh R, Farasyn T, Crowe A, Liu Q, Pahwa S, Alam K, Neuhoff S, Hatley O, Ding K, Yue W. Assessing OATP1B1- and OATP1B3-Mediated Drug-Drug Interaction Potential of Vemurafenib Using R-Value and Physiologically-Based Pharmacokinetic Models. J Pharm Sci 2020; 110:314-324. [PMID: 32590030 DOI: 10.1016/j.xphs.2020.06.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 11/19/2022]
Abstract
Organic anion transporting polypeptides (OATP) 1B1 and OATP1B3 are important determinants of transporter-mediated drug-drug interactions (DDIs). Current studies assessed the OATP1B1 and OATP1B3-mediated DDI potential of vemurafenib, a kinase inhibitor drug with high protein binding and low aqueous solubility, using R-value and physiologically-based pharmacokinetic (PBPK) models. The total half-maximal inhibitory concentration (IC50,total) values of vemurafenib against OATP1B1 and OATP1B3 were determined in 100% human plasma in transporter-overexpressing human embryonic kidney 293 stable cell lines. The unbound fraction of vemurafenib in human plasma before (fu,plasma) and after addition into the uptake assay plate (fu,plasma,inc) were determined by rapid equilibrium dialysis. There was no statistically significant difference between fu,plasma and fu,plasma,inc. Vemurafenib IC50,total values against OATP1B1 and OATP1B3 are 175 ± 82 and 231 ± 26 μM, respectively. The R-values [R = 1 + fu,plasma × Iin,max/(fu,plasma,inc × IC50,total)] were then simplified as R = 1+Iin,max/IC50,total, and were 1.76 and 1.57 for OATP1B1 and OATP1B3, respectively. The simulated pravastatin AUC ratio was 1.28 when a single dose of pravastatin (40 mg) was co-administered with vemurafenib (960 mg, twice daily) at steady-state, compared to pravastatin alone. Both R-value and PBPK models predict that vemurafenib has the potential to cause OATP1B1- and OATP1B3-mediated DDIs.
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Affiliation(s)
- Ruhul Kayesh
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Taleah Farasyn
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Alexandra Crowe
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Qiang Liu
- ARL Bio Pharma, Oklahoma City, Oklahoma 73104
| | - Sonia Pahwa
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Khondoker Alam
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Sibylle Neuhoff
- Certara UK Ltd, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ United Kingdom
| | - Oliver Hatley
- Certara UK Ltd, Simcyp Division, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ United Kingdom
| | - Kai Ding
- Department of Biostatistics and Epidemiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104
| | - Wei Yue
- Department of Pharmaceutical Sciences, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104.
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3
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Blood plasma influences anti-aggregatory potency of prostaglandins: effect of albumin. Inflammopharmacology 2010; 7:179-85. [PMID: 18597158 DOI: 10.1007/bf02918389] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/1998] [Revised: 02/15/1999] [Accepted: 03/16/1999] [Indexed: 10/21/2022]
Abstract
The anti-aggregatory effects of prostaglandins (PGs) were compared in platelet-rich plasma (PRP) with that in washed platelets (WP). PGE(1), 13,14-dihydro-PGE(1), 5,6-dihydro-PGE(3) and ethyl ester of PGE(1) had the same potency in both platelet preparations. Iloprost was significantly more potent in WP compared to PRP, while 5,6-trans-PGE(2) and PGE(3) had higher potency in PRP than in WP. Albumin (35 mg/ml) in WP decreased the potency of iloprost but did not change the IC(50) value for PGE(3). In PRP, PGs were 1.5-2.8 times more potent when incubated 3 min as compared to 30 s, while in WP, the incubation time did not affect the IC(50) values for PGs. In WP with albumin, the potency of iloprost was significantly lower when it was incubated 30 s as compared to 3 min. Thus, plasma albumin is responsible for time-dependent effect of PGs and for the lower potency of iloprost but not for the higher potency of PGs in PRP.
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4
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Huang SC. Endothelin receptors in lower esophageal sphincter circular smooth muscle. ACTA ACUST UNITED AC 2005; 127:27-35. [PMID: 15680467 DOI: 10.1016/j.regpep.2004.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2004] [Accepted: 10/21/2004] [Indexed: 10/26/2022]
Abstract
To characterize endothelin (ET) receptors in the lower esophageal sphincter, we measured contraction of transverse strips from the guinea-pig lower esophageal sphincter induced by ET-related peptides and binding of 125I-ET-1 to cell membranes prepared from the lower esophageal sphincter circular muscle. Visualization of 125I-ET-1 binding sites in tissue was performed by autoradiography. ET-1 or ET-2 alone did not cause contraction or relaxation in resting strips. However, in carbachol precontracted lower esophageal sphincter strips, ET-1 and ET-2 caused marked, tetrodotoxin-insensitive relaxation. The ET-1-induced relaxation was abolished by BQ-123, an ETA receptor selective antagonist, but not inhibited by BQ-788, an ETB receptor selective antagonist. ET-3 and sarafotoxin S6c, a selective ETB receptor agonist, did not cause relaxation in the carbachol precontracted muscle strips. These clearly indicate that ETA receptors mediate relaxation. On the other hand, ET-3 and sarafotoxin S6c caused tetrodotoxin and atropine-insensitive contraction in the resting strips. The sarafotoxin S6c-induced contraction was inhibited by BQ-788, but not by BQ-123. Furthermore, ET-1 and ET-2 caused contraction of the resting muscle strips after pretreatment with BQ-123. This ET-1-induced contraction was also inhibited by BQ-788. Taken together, these indicate that ETB receptors mediate contraction. Autoradiography localized 125I-ET-1 binding to the lower esophageal sphincter circular muscle as well as longitudinal muscle of the esophagus. Binding of 125I-ET-1 to cell membranes prepared from the circular smooth muscle was saturable and specific. Analysis of dose-inhibition curves indicated the presence of two classes of receptors, ETA and ETB receptors. These results demonstrate that the guinea-pig lower esophageal sphincter possesses ETA receptors mediating relaxation and ETB receptors mediating contraction.
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Affiliation(s)
- Shih-Che Huang
- Department of Internal Medicine, Tzu Chi General Hospital and Tzu Chi University, 707, Section 3, Chung-Yang Road, Hualien 970, Taiwan.
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5
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Huang SC, Chang BS. Endothelin causes contraction of human esophageal muscularis mucosae through interaction with both ETA and ETB receptors. ACTA ACUST UNITED AC 2004; 117:179-86. [PMID: 14749038 DOI: 10.1016/j.regpep.2003.10.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Endothelin (ET) causes contraction of the muscularis mucosae in the guinea pig esophagus, but its role in the human esophagus remains unknown. To investigate effects of ET in the human esophagus, we measured contraction of isolated human esophageal muscularis mucosae strips caused by ET related peptides and binding of 125I-ET-1 to cell membranes prepared from the human esophageal muscularis mucosae. Autoradiography demonstrated specific binding of 125I-ET-1 to the muscularis mucosae and muscularis propria (muscularis externa) of the human esophagus. ET-1 caused tetrodotoxin and atropine-insensitive contraction of muscularis mucosae strips. In terms of the maximal tension of contraction, ET-1 and ET-2 were equal in efficacy. The relative potencies for ET related peptides to cause contraction were ET-1=ET-2>ET-3>sarafotoxin S6c (SX6c), an ETB receptor agonist. ET-1 caused contraction was mildly inhibited by BQ-123, an ETA receptor antagonist, and not by BQ-788, an ETB receptor antagonist. It was moderately inhibited by the combination of both antagonists, indicating synergistic inhibition. Furthermore, desensitization to SX6c with SX6c pretreatment failed to abolish the contractile response to ET-1, which was completely inhibited by BQ-123. These indicate the involvement of both ETA and ETB receptors in the contraction. Binding of 125I-ET-1 to cell membranes of the muscularis mucosae was saturable and specific. Analysis of dose-inhibition curves demonstrated the presence of ETA and ETB receptors. This study demonstrates that, the muscularis mucosae of the human esophagus, similar to that of the guinea pig esophagus, possesses both ETA and ETB receptors mediating muscle contraction.
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Affiliation(s)
- Shih-Che Huang
- Department of Internal Medicine, Tzu Chi General Hospital and Tzu Chi University, 707, Section 3, Chung-Yang Road, Hualien 970, Taiwan.
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6
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Huang SC. Endothelin ET(A) but not ET(B) receptors mediate contraction of common bile duct. REGULATORY PEPTIDES 2003; 113:131-8. [PMID: 12686472 DOI: 10.1016/s0167-0115(03)00004-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Endothelin (ET) causes contraction of the gallbladder. To investigate effects of ET in the common bile duct, we measured contraction of longitudinal muscle strips from guinea pig common bile ducts induced by ET-related peptides and binding of 125I-ET-1 to cell membranes prepared from the common bile duct. Visualization of 125I-ET-1 binding sites in tissue was performed by autoradiography. ET-1 caused tetrodotoxin and atropine-insensitive contraction. In terms of maximal tension of contraction, ET-1, ET-2 and ET-3 were equal in efficacy. However, sarafotoxin S6c, a selective ET(B) receptor agonist, caused only a negligible contraction. The relative potencies for ET isopeptides to cause contraction were ET-1=ET-2>ET-3. The ET-1-induced contraction was inhibited by BQ-123, an ET(A)-receptor-selective antagonist, but not by BQ-788, an ET(B)-receptor-selective antagonist. In addition, the combination of both antagonists, BQ-123 and BQ-788, inhibited ET-1 induced contraction but did not potentiate the inhibition caused by BQ-123 alone. These indicate that ET(A) but not ET(B) receptors mediate the contraction. Autoradiography localized 125I-ET-1 binding to the smooth muscle layer. Binding of 125I-ET-1 to the smooth muscle cell membranes was saturable and specific. Analysis of dose-inhibition curves indicated the presence of ET(A) and ET(B) receptors. These results demonstrate that ET causes contraction of longitudinal muscle of the common bile duct. Different from the gallbladder, which possesses both ET(A) and ET(B) receptors cooperating to mediate muscle contraction, the common bile duct possesses two classes of ET receptors, but only the ET(A) receptor mediates the contraction.
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Affiliation(s)
- Shih-Che Huang
- Department of Internal Medicine, Tzu Chi General Hospital and Tzu Chi University, 707 Section 3, Chung-Yang Road, 970, Hualien, Taiwan
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7
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Huang SC. Two classes of endothelin receptors mediating contraction in esophageal muscularis mucosae. REGULATORY PEPTIDES 2002; 105:189-96. [PMID: 11959373 DOI: 10.1016/s0167-0115(02)00021-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Endothelin (ET) causes contraction of the esophageal muscularis mucosae. To characterize the ET receptor subtypes involved in contraction, we measured contraction of isolated muscularis mucosae strips caused by ET-related peptides and binding of (125)I-ET-1 to cell membranes prepared from the guinea pig esophageal muscularis mucosae. Autoradiography demonstrated (125)I-ET-1 binding to the muscularis mucosae and muscularis propria. ET-1 caused tetrodotoxin and atropine-insensitive contraction of esophageal muscularis mucosae strips. The relative potencies for ET isopeptides to cause contraction were ET-1=ET-2>ET-3. FR-139317, an ET(A) receptor antagonist, or BQ-788, an ET(B) receptor antagonist, alone did not alter responses to ET-1. However, the combination of both antagonists almost abolished the ET-1-induced contraction, indicating synergistic inhibition. Desensitization to sarafotoxin S6c, an ET(B) receptor agonist, failed to abolish the response to ET-1, which was completely inhibited by FR-139317. These indicate the involvement of both ET(A) and ET(B) receptors in the contraction. Binding of (125)I-ET-1 to cell membranes of the muscularis mucosae was saturable and specific. Analysis of dose-inhibition curves demonstrated the presence of ET(A) and ET(B) receptors. This study demonstrates that the esophageal muscularis mucosae possesses both ET(A) and ET(B) receptors mediating muscle contraction. There is cooperation between these two subtypes of ET receptors in the esophagus mediating muscle contraction.
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Affiliation(s)
- Shih-Che Huang
- Department of Internal Medicine, Tzu Chi General Hospital and Tzu Chi University, 707 Section 3, Chung-Yang Road, 970, Hualien, Taiwan.
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8
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Ohlsson B, Borg K, Rehfeld JF, Axelson J, Sundler F. The method of administration of cholecystokinin determines the effects evoked in the pancreas. Pancreas 2001; 23:94-101. [PMID: 11451154 DOI: 10.1097/00006676-200107000-00014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Earlier studies have shown different effects on cell proliferation and weight characteristics by sulfated cholecystokinin-8 (CCK-8S) in the rat pancreas when the peptide has been administered continuously rather than intermittently. The aim of this study was as follows: (i) to compare the effect of continuous infusion and of intermittent injections of CCK-8S on cell proliferation, weight gain, and induction of apoptosis and (ii) to examine the effect of injections of CCK-8S on CCK-A receptor gene expression in the rat pancreas. Male Sprague-Dawley rats had subcutaneous continuous infusion of CCK-8S in a dose of 5 microg/kg/h or 1% bovine serum albumin (BSA) (vehicle) by implanted osmotic minipumps. The rats were killed after 4 days. Other rats were either injected subcutaneously only once or injected twice daily for 3 days with either 6 microg of CCK dissolved in 0.5 mL BSA or 0.5 mL BSA alone. The rats were killed 1, 3, 6, and 12 hours after the last injection. One hour before death they received 5-bromo-2-deoxyuridine (BrdU) intraperitoneally to localize and quantitate the cell proliferation. Plasma was collected for analysis of CCK. The pancreas was dissected and immunohistochemistry was performed for analysis of the expression of the apoptosis promoting protein bax and the apoptosis inhibiting protein bcl-2, and for BrdU and CCK-A receptor localization. In situ hybridization (ISH) was used for examination and semiquantification of CCK-A receptor mRNA expression. Continuous infusion of CCK-8S led to a sixfold increase in plasma CCK and a 40% increase in pancreatic weight without any effect on BrdU labeling. Immunohistochemistry revealed decreased tissue expression of bax but unaffected expression of bcl-2. Intermittent injections of CCK-8S led to hyper-CCK-emia with increased incorporation of BrdU, indicating increased cell proliferation but no increase in pancreatic weight. Immunohistochemistry showed increased expression of bax, whereas bcl-2 remained unchanged. Immunofluorescence and ISH for the CCK-A receptor and its gene expression, respectively, showed a lowest intensity at 3 hours after CCK-8S injections. The results indicate that decreased apoptosis could explain the increased pancreatic weight during continuous infusion of CCK-8S. An increased apoptosis could explain the lack of pancreatic weight gain upon intermittent injections of CCK-8S despite the stimulation of cell proliferation. Injections of CCK-8S only transiently decreased the tissue levels of its receptor.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Bromodeoxyuridine
- Cell Division/drug effects
- DNA Replication
- Drug Administration Schedule
- Fluorescent Antibody Technique, Indirect
- Gene Expression Regulation/drug effects
- Genes, bcl-2
- In Situ Hybridization
- Infusion Pumps, Implantable
- Infusions, Intravenous
- Injections, Subcutaneous
- Male
- Organ Size/drug effects
- Pancreas/anatomy & histology
- Pancreas/cytology
- Pancreas/drug effects
- Proto-Oncogene Proteins/biosynthesis
- Proto-Oncogene Proteins/genetics
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Rats
- Rats, Sprague-Dawley
- Receptor, Cholecystokinin A
- Receptors, Cholecystokinin/biosynthesis
- Receptors, Cholecystokinin/genetics
- Sincalide/administration & dosage
- Sincalide/analogs & derivatives
- Sincalide/pharmacology
- bcl-2-Associated X Protein
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Affiliation(s)
- B Ohlsson
- Department of Surgery, University of Lund, Sweden.
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9
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Huang SC, Lee MC, Wei CK, Huang SM. Endothelin receptors in human and guinea-pig gallbladder muscle. REGULATORY PEPTIDES 2001; 98:145-53. [PMID: 11231044 DOI: 10.1016/s0167-0115(00)00238-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We measured contraction of muscle strips caused by endothelin (ET) isopeptides and binding of (125)I-ET-1 to muscle cell membranes prepared from human and guinea-pig gallbladders. Visualization of (125)I-ET-1 binding sites in tissue was performed by autoradiography. Results in human were similar to those in guinea-pig. ET-1 caused tetrodotoxin and atropine-insensitive contraction. The relative potencies for ET isopeptides to cause contraction were ET-1=ET-2>ET-3. ET-1 caused contraction was only slightly inhibited by BQ-123 (potent ET(A) receptor antagonist) and not by BQ-788 (potent ET(B) receptor antagonist). It was inhibited by the combination of both. Autoradiography localized (125)I-ET-1 binding to the smooth muscle layer. Binding of (125)I-ET-1 to muscle cell membranes was saturable and specific. Analysis of dose-inhibition curves demonstrated the presence of two classes of receptors. One class (ET(A) receptor) had a high affinity for ET-1 and ET-2 but a low affinity for ET-3, and the other (ET(B) receptor) a high affinity for ET-1, ET-2 and ET-3. These results demonstrate that similar to guinea-pig, human gallbladder possesses both ET(A) and ET(B) receptors cooperating to mediate muscle contraction.
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Affiliation(s)
- S C Huang
- Department of Internal Medicine, Tzu Chi General Hospital and Tzu Chi University, 707 Section 3, Chung-Yang Road, 970, Taiwan, Hualien, China.
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10
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Wei JY, Wang YH. Effect of CCK pretreatment on the CCK sensitivity of rat polymodal gastric vagal afferent in vitro. Am J Physiol Endocrinol Metab 2000; 279:E695-706. [PMID: 10950839 DOI: 10.1152/ajpendo.2000.279.3.e695] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To prevent the blood-borne interference and reflex actions via neighboring organs and the central nervous system, the study was conducted in an in vitro isolated stomach-gastric vagus nerve preparation obtained from overnight-fasted, urethan-anesthetized rats. Afferent unit action potentials were recorded from the gastric branch of the vagus nerve. The left gastric artery was catheterized for intra-arterial injection. In vitro we found that 1) 55/70 gastric vagal afferents (GVAs) were polymodal, responding to CCK-8 and mechanical stimuli, 13 were mechanoreceptive, and 2 were CCK-responsive; 2) sequential or randomized intra-arterial injections of CCK-8 (0.1-200 pmol) dose-dependently increased firing rate and reached the peak rate at 100 pmol; 3) the action was suppressed by CCK-A (Devazepide) but not by CCK-B (L-365,260) receptor antagonist; 4) neither antagonist blocked the mechanosensitivity of GVA fibers. These results are consistent with corresponding in vivo well-documented findings. Histological data indicate that the layered structure of the stomach wall was preserved in vitro for 6-8 h. Based on these results, it seems reasonable to use the in vitro preparation for conducting a study that is usually difficult to be performed in vivo. For instance, because there was no blood supply in vitro, the composition of the interstitial fluid, i.e., the ambient nerve terminals, can be better controlled and influenced by intra-arterial injection of a defined solution. Here we report that acutely changing the ambient CCK level by a conditioning stimulus (a preceding intra-arterial injection of increasing doses of CCK-8) reduced the CCK sensitivity of GVA terminals to a subsequent test stimulus (a constant dose of CCK-8 intra-arterial injection).
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Affiliation(s)
- J Y Wei
- Digestive Diseases Division, Department of Medicine, Center for Ulcer Research and Education/Digestive Diseases Research Center and Brain Research Institute, University of California Los Angeles School of Medicine, 90095, USA
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11
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Schaeffer P, Nestor AL, Prabonnaud V, Bachy A, Laplace MC, Keane PE, Bignon E, Herbert JM. Characterisation of the effects of SR146131, a novel non-peptide CCK(1) receptor agonist, on IMR-32 human neuroblastoma cells. Eur J Pharmacol 2000; 397:303-10. [PMID: 10844128 DOI: 10.1016/s0014-2999(00)00274-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The effect of ¿2-[4-(4-chloro-2, 5-dimethoxy-phenyl)-5-[2-cyclohexyl-ethyl)-thiazol-2-ylcarbamoy l]-5, 7-dimethyl-indol-1-yl¿-acetic acid (SR146131), a novel non-peptide agonist of cholecystokinin (CCK) CCK(1) receptors, was compared to the effect of sulphated cholecystokinin octapeptide (CCK-8-S) on CCK(1) receptors of the human neuroblastoma cell line IMR-32. SR146131 inhibited [125I]CCK-8-S binding to IMR-32 cells at nanomolar concentrations. SR146131 and CCK-8-S increased intracellular free Ca(2+) levels ([Ca(2+)](i)) in the same concentration range (EC(50)=6+/-2.3 and 1.3+/-0.14 nM, respectively). Although the shape of the [Ca(2+)](i) increase induced by CCK-8-S and SR146131 was slightly different, extracellular Ca(2+) removal affected the response of both compounds to a similar degree, and the response of both compounds was essentially due to Ca(2+) release from intracellular stores. This was also confirmed by measuring the [Ca(2+)](i) response of single cells: both compounds induced [Ca(2+)](i) oscillations at subnanomolar concentrations and elicited a large peak increase in [Ca(2+)](i) at higher concentrations (EC(50)=0.5+/-0.04 and 5.7+/-1.9 nM for CCK-8-S and SR146131, respectively). Both CCK-8-S and SR146131 induced a sustained increase of phosphoinositide turnover in these cells, and acted at similar concentrations (EC(50)=2.7+/-0.7 and 6+/-3.1 nM, respectively), although the maximal effect of SR146131 was somewhat lower than the effect of CCK-8-S. These data show that SR146131 activates human CCK(1) receptors on IMR-32 cells in a manner and with a potency similar to that of CCK-8-S.
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Affiliation(s)
- P Schaeffer
- Cardiovascular/Thrombosis Research Department, Sanofi Recherche, 195 Route d'Espagne, 31036, Toulouse, France
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12
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Blanchet F, Gauchy C, Perez S, Glowinski J, Kemel ML. Role of arachidonic acid in the regulation of the NMDA-evoked release of acetylcholine in striatal compartments. Synapse 1999; 31:140-50. [PMID: 10024011 DOI: 10.1002/(sici)1098-2396(199902)31:2<140::aid-syn7>3.0.co;2-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The role of endogenously released arachidonic acid in the control of the NMDA (50 microM)-evoked release of [3H]-acetylcholine previously formed from [3H]-choline was investigated in striosome-enriched areas and in the matrix of the rat striatum using a microsuperfusion procedure in vitro. Experiments were performed with either mepacrine (0.2 microM) or bovine serum albumin (BSA, 0.02%) which inhibits phospholipase A2 activity or binds endogenously released arachidonic acid, respectively. Both treatments similarly reduce the NMDA-evoked release of [3H]-acetylcholine, this effect being more pronounced in striosomes than in the matrix. These reductions result from a facilitation of dopamine release, since they were not observed in the presence of (-)sulpiride, the D2 dopamine receptor antagonist. Moreover, the superfusion with BSA was shown to enhance the release of [3H]-dopamine (formed from [3H]-tyrosine), this effect being of larger amplitude in striosomes than in the matrix. In control conditions, due to the blockade of the presynaptic inhibitory effect of GABA on dopamine release, bicuculline (GABA(A) receptor antagonist) reduces the NMDA-evoked release of [3H]-acetylcholine in both striatal compartments. Bicuculline was no longer effective following superfusions with either mepacrine or BSA, suggesting that these treatments eliminate the GABAergic presynaptic inhibitory control on dopamine transmission and thus lead to the dopamine-mediated inhibition of [3H]-acetylcholine release. These results indicate that arachidonic acid endogenously formed under weak stimulation of NMDA receptors contributes to the regulation of the evoked release of [3H]-acetylcholine by facilitating GABAergic transmission and that this process is more important in striosomes than in the matrix.
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Affiliation(s)
- F Blanchet
- Chaire de Neuropharmacologie, INSERM U114, Collège de France, Paris.
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