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Fayyaz A, Ranta VP, Toropainen E, Vellonen KS, Ricci GD, Reinisalo M, Heikkinen EM, Gardner I, Urtti A, Jamei M, Del Amo EM. Ocular Intracameral Pharmacokinetics for a Cocktail of Timolol, Betaxolol, and Atenolol in Rabbits. Mol Pharm 2020; 17:588-594. [PMID: 31794668 DOI: 10.1021/acs.molpharmaceut.9b01024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The mechanisms of drug clearance from the aqueous humor are poorly defined. In this study, a cocktail approach was used to simultaneously determine the pharmacokinetics of three β-blocker agents after intracameral (ic) injection into the rabbit eyes. Aqueous humor samples were collected and analyzed using LC-MS/MS to determine drug concentrations. Pharmacokinetic parameters were obtained using a compartmental fitting approach, and the estimated clearance, volume of distribution, and half-life values were the following: atenolol (6.44 μL/min, 687 μL, and 73.87 min), timolol (19.30 μL/min, 937 μL, and 33.64 min), and betaxolol (32.20 μL/min, 1421 μL, and 30.58 min). Increased compound lipophilicity (atenolol < timolol < betaxolol) resulted in higher clearance and volume of distributions in the aqueous humor. Clearance of timolol and betaxolol is about 10 times higher than the aqueous humor outflow, demonstrating the importance of other elimination routes (e.g., uptake to iris and ciliary body and subsequent elimination via blood flow).
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Affiliation(s)
- Anam Fayyaz
- Certara UK, Simcyp Division , Level 2-Acero, 1 Concourse Way , Sheffield S1 2BJ , U.K.,University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland
| | - Veli-Pekka Ranta
- University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland
| | - Elisa Toropainen
- University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland
| | - Kati-Sisko Vellonen
- University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland
| | - Giuseppe D'Amico Ricci
- University of Sassari , Department of Biomedical Sciences , Sassari , Italy.,Asl Città di Torino, Ospedale Oftalmico di Torino , U.O.C Oculistica 2, Ospedale San Giovanni Bosco di Torino , Torino , Italy
| | - Mika Reinisalo
- University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland.,Institute of Clinical Medicine, Department of Ophthalmology, Faculty of Health Sciences , University of Eastern Finland , 70210 Kuopio , Finland
| | - Emma M Heikkinen
- University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland
| | - Iain Gardner
- Certara UK, Simcyp Division , Level 2-Acero, 1 Concourse Way , Sheffield S1 2BJ , U.K
| | - Arto Urtti
- University of Eastern Finland , School of Pharmacy, Biopharmaceutics , Yliopistonranta 1 , 70210 Kuopio , Finland
| | - Masoud Jamei
- Certara UK, Simcyp Division , Level 2-Acero, 1 Concourse Way , Sheffield S1 2BJ , U.K
| | - Eva M Del Amo
- University of Manchester , Division of Pharmacy & Optometry , Oxford Road , Manchester M13 9PL , U.K
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Hong SJ. Mechanism of endothelin-1-induced cytosolic Ca(2+) mobility in cultured H9c2 myocardiac ventricular cells. Cell Signal 2002; 14:811-7. [PMID: 12135702 DOI: 10.1016/s0898-6568(02)00020-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of endothelin-1 (ET-1) on the intracellular free Ca(2+) ([Ca(2+)](i)) mobility in cultured H9c2 myocardiac ventricular cells was studied after loading with fura-2-AM. In Ca(2+)-containing buffer, ET-1 induced [Ca(2+)](i) rise from 10(-7) to 10(-9) M. ET-1 induced [Ca(2+)](i), which was composed of a first small peak and a secondary persistent plateau. In Ca(2+)-free buffer, pretreatment with 10(-7) M ET-1 inhibited the thapsigargin and carbonylcyanide m-chlorophenylhydrazone (CCCP)-induced [Ca(2+)](i) increase. Meanwhile, pretreatment with thapsigargin and CCCP also inhibited ET-1-induced [Ca(2+)](i) rise. In Ca(2+)-containing buffer, the ET(A) receptor antagonist (BQ123) completely abolished the secondary rising peak and plateau. Conversely, the ET(B) receptor antagonist (BQ788) completely inhibited the first small peak and secondary peak plateau. Nifedipine and La(3+) also abolished the 10(-7) M ET-1-induced [Ca(2+)](i) in the first rising peak. The internal Ca(2+) release induced by ET-1 was inhibited by U73122 (phospholipase C inhibitor), propranolol (phospholipase D inhibitor) and aristolochic acid (phospholipase A2 inhibitor). After incubation of 10(-7) M ET-1 in Ca(2+)-free buffer, the addition of 5 mM CaCl(2) increased Ca(2+) influx, implying that release of Ca(2+) from internal stores further induces capacitative Ca(2+) entry. Taken together, these results suggest that both ET(A) and ET(B) receptors are involved in ET-1-induced [Ca(2+)](i) rise in H9c2 myocardiac ventricular cells. Whereas ET(B) receptor seems to mediate the initial Ca(2+) influx via L-type Ca(2+) channel, ET(A) receptor appears to be involved in the subsequent Ca(2+) release from endoplasmic reticulum and mitochondria Ca(2+) stores.
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Affiliation(s)
- Show-Jen Hong
- Department of Pharmacology, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung, Taiwan.
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Nakamura S, Taniguchi T, Suzuki F, Akagi Y, Muramatsu I. Evaluation of alpha1-adrenoceptors in the rabbit iris: pharmacological characterization and expression of mRNA. Br J Pharmacol 1999; 127:1367-74. [PMID: 10455286 PMCID: PMC1760646 DOI: 10.1038/sj.bjp.0702675] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Subtypes of alpha1-adrenoceptor in rabbit iris have been examined in functional, binding and molecular biological experiments. In functional studies, exogenous and endogenous noradrenaline produced contractions of the iris dilator muscle. The contractile responses to noradrenaline were competitively antagonized by a range of alpha1-adrenoceptor antagonists (pA2 values): prazosin (8.1), WB4101 (8.2), BMY7378 (5.9), YM617 (9.5), JTH-601 (8.8), HV723 (7.8) and KMD-3213 (9.8). The same order of inhibitory potency was seen in the adrenergic responses to electrical stimulation. This affinity profile corresponds well to that of the putative alpha1L-adrenoceptor, which has been proposed in lower urinary tract tissues. In binding studies on rabbit iris membrane however, prazosin, KMD-3213 and WB4101 displayed high affinity (pKd or pKi: 9.6, 10.3, 9.6, respectively), and BMY7378 displayed low affinity (pKi: 6.9). These results show that the binding sites typically correspond to alpha1A-adrenoceptor subtype in character, and we could not detect the significant amount of alpha1L-adrenoceptor subtype. The expression of the three distinct mRNAs that encode proteins of alpha1a-, alpha1b- and alpha1d-adrenoceptors was studied using reverse transcription-polymerase chain reaction (RT-PCR). RT-PCR demonstrated the strongest expression of the alpha1a-adrenoceptor, weak expression of the alpha1b-adrenoceptor and undetectable expression of the alpha1d-adrenoceptor. The present study suggests that alpha1A-adrenoceptor is a major subtype detectable in binding and RT-PCR studies in rabbit iris, but that the adrenergic contractions of iris dilator muscle are mediated via activation of alpha1-adrenoceptor subtype having low affinity for prazosin and WB4101.
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MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Binding, Competitive/drug effects
- Clonidine/pharmacology
- Dose-Response Relationship, Drug
- Gene Expression/drug effects
- In Vitro Techniques
- Indoles/pharmacology
- Iris/drug effects
- Iris/physiology
- Male
- Muscle Contraction/drug effects
- Norepinephrine/pharmacology
- Oxymetazoline/pharmacology
- Phenylephrine/pharmacology
- Prazosin/pharmacology
- RNA, Messenger/drug effects
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rabbits
- Receptors, Adrenergic, alpha-1/genetics
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-1/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Tritium
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Affiliation(s)
- Seigo Nakamura
- Department of Pharmacology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, 910-1193, Japan
- Department of Ophthalmology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, 910-1193, Japan
| | - Takanobu Taniguchi
- Department of Pharmacology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, 910-1193, Japan
| | - Fumiko Suzuki
- Department of Pharmacology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, 910-1193, Japan
| | - Yoshio Akagi
- Department of Ophthalmology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, 910-1193, Japan
| | - Ikunobu Muramatsu
- Department of Pharmacology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, 910-1193, Japan
- Author for correspondence:
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