Journal of pharmacological methods最新文献

{"title":"A model of multivessel coronary artery disease using conscious, chronically instrumented dogs","authors":"J.Craig Hartman,&nbsp;David C. Warltier","doi":"10.1016/0160-5402(90)90014-C","DOIUrl":"10.1016/0160-5402(90)90014-C","url":null,"abstract":"<div><p>The present investigation was undertaken to develop a reproducible model of multivessel coronary artery disease including a total occlusion of one vessel and a stenosis of an adjacent vessel in chronically instrumented dogs. Utilizing sterile techniques, we surgically prepared dogs for measurement of heart rate, arterial pressure, left ventricular pressure, and blood flow velocity in the left anterior descending (LAD) and left circumflex (LCCA) coronary arteries. A hydraulic occluder and Ameroid constrictor were implanted around the LAD and LCCA, respectively. Pairs of piezoelectric crystals were implanted within the subendocardium of the LAD and LCCA perfusion territories to measure regional contractile function (segment shortening). A catheter was placed in the left atrial appendage for injection of radioactive microspheres to measure regional myocardial perfusion. Beginning on the second day following implantation, 25, 50, and 100 μg bolus injections of adenosine were administered daily via the left atrium to evaluate LAD and LCCA coronary reserve. Although LAD reserve remained intact, the hyperemic response of the LCCA was progressively attenuated as stenosis severity increased during slow closure of the Ameroid constrictor. When the LCCA vasodilator response to adenosine was reduced by 50% (moderate stenosis; no change in resting flow velocity) or 70% (severe stenosis; 20% reduction in resting flow velocity), the LAD was acutely occluded (<em>via</em> inflation of the hydraulic occluder) to simulate multivessel coronary artery disease. After a hemodynamic steady state was established during coronary occlusion, radioactive microspheres were administered to compare regional perfusion within normal myocardium to flow in myocardium supplied by the occluded or stenotic coronary arteries. In dogs with a stenosis of moderate severity, transmural myocardial blood flow was significantly decreased (− 83%) only in the occluded zone. However, in dogs with a severe coronary artery stenosis, reductions in perfusion in both stenotic (−31%) and occluded (− 87%) regions were demonstrated. Subendocardial/subepicardial flow ratios were significantly reduced in both stenotic and totally occluded regions in the presence of severe stenosis, but this occurred only in the occluded (LAD) zone of dogs with a moderate LCCA stenosis. This preparation provides a model whereby the vasodilator reserve of a progressively constricted coronary artery can be quantified and simultaneously compared to the reserve of a normal vessel. With acute occlusion of the normal artery, a multivessel disease</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 297-310"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90014-C","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13443561","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Author index volumes 23 and 24","authors":"","doi":"10.1016/0160-5402(90)90017-F","DOIUrl":"https://doi.org/10.1016/0160-5402(90)90017-F","url":null,"abstract":"","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 333-334"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90017-F","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137068247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A sensitive in vitro functional assay to detect K+ — channel-dependent vasodilators","authors":"Kaushik D. Meisheri,&nbsp;Loretta A. Cipkus Dubray,&nbsp;Joseph J. Oleynek","doi":"10.1016/0160-5402(90)90010-I","DOIUrl":"10.1016/0160-5402(90)90010-I","url":null,"abstract":"<div><p>This study describes a sensitive in vitro relaxation assay using isolated rabbit mesenteric artery to detect the activity of a vasodilator as a K⁺-channel activator. Thus, comparison of several known K⁺-channel activators was made with other vasodilators known to work via various cellular mechanisms. The vasodilators used were minoxidil sulfate (MNXS; 5 μM), BRL-34915 (cromakalim, 0.1 μM), nicorandil (10 μM), pinacidil (1 μM), diazoxide (100 μM), sodium nitroprusside (10 μM), forskolin (1 μM), D600 (0.5 and 10 μM), hydralazine (10 μM), and viprostal (PGE1 analog, 5 μM). The concentrations chosen were equipotent to produce greater than 80% relaxation of the maximal norepinephrine (NE) (5 μM) contraction. At these concentrations, MNXS, cromakalim, pinacidil, nicorandil, and diazoxide were found to be ineffective in producing relaxation of 80 mM K⁺-contractions. Subsequently, pretreatment of tissues with 20 mM K⁺ before NE contraction was found to attenuate relaxation significantly by these agents, but had no effect on the relaxations by forskolin or D600. These initial criteria helped to establish cromakalim, pinacidil, nicorandil, and diazoxide as compounds acting similarly to MNXS as K⁺-channel-dependent. In another set of experiments, the effects of tetraethylammonium (TEA) (10 mM), Ba²⁺ (0.5 mM), and glyburide (1 μM) as K⁺-channel blockers were examined. Again it was found that these blockers had the most inhibitory effect on the class of compounds identified as K⁺ channel activators. Additionally, it was found that these K⁺-channel activators were without any significant effect on the NE-sensitive intracellular Ca²⁺ release as studied by contraction in a Ca²⁺-free solution. Thus, this series of functional criteria clearly show that the profile of these K⁺-channel activators is distinctly different from the vasodilators working via other mechanisms such as cyclic AMP (cAMP) (forskolin), cyclic GMP (cCMP) (nitroprusside), and Ca²⁺ antagonists (D600). It is suggested that appropriately defined, systematic functional studies, such as the one described here, can provide a sensitive and reproducible vascular model to discover and delineate the role of pharmacologically relevant mechanisms for vasodilation.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 251-261"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90010-I","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13443030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subject index volumes 23 and 24","authors":"","doi":"10.1016/0160-5402(90)90018-G","DOIUrl":"https://doi.org/10.1016/0160-5402(90)90018-G","url":null,"abstract":"","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 335-337"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90018-G","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137068248","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The doppler method for measuring cardiac output in conscious rabbits: Validation studies, uses, and limitations","authors":"Robert P. Hof ,&nbsp;Akiko Hof ,&nbsp;Rolf P. Stürm","doi":"10.1016/0160-5402(90)90011-9","DOIUrl":"10.1016/0160-5402(90)90011-9","url":null,"abstract":"<div><p>The velocity of blood in the rabbit aorta is very fast, approaching the limits of some pulsed directional Doppler flow meters. Therefore, we thoroughly evaluated a 20- and a 10-MHz device for measuring cardiac output in rabbits. Flow probes were implanted around the ascending aorta and catheters were implanted into the left atrium (for microsphere injection), femoral artery, and vein. About 2 weeks later, cardiac output was determined with the Dopper method and simultaneously with tracer microspheres. Cardiac output was manipulated with isoproterenol, dihydralazine, guanfacine, or alinidine, intravenously.</p><p>With the 20-MHz device, only normal and decreased cardiac output could be measured accurately, even with a 60° implantation angle of the crystals. The 10MHz device yielded accurate measurements also at very high flow. Surprisingly, at high aortic flow rates, both the 10- and the 20-MHz devices were unable to measure correctly diastolic flow, which is close to zero. It was necessary to adjust the position of the late diastolic Doppler signal manually to the electrical zero line. With this precaution, the 10-MHz device yielded an excellent correlation between mean Doppler signal and cardiac output. Cardiac output can be measured in absolute flow units if the flow-probe can be calibrated in vivo with an independent, accurate method about 2 wk after implantation. The baroreflex was not affected by the implanted flow probes. Within these limits, Doppler flow meters are good tools to assess drug effects on cardiac output in conscious rabbits.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 263-276"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90011-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13443557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessment of myeloperoxidase activity in whole rat kidney","authors":"L.M. Hillegass,&nbsp;D.E. Griswold,&nbsp;B. Brickson,&nbsp;C. Albrightson-Winslow","doi":"10.1016/0160-5402(90)90013-B","DOIUrl":"10.1016/0160-5402(90)90013-B","url":null,"abstract":"<div><p>A method to quantitate myeloperoxidase (MPO) activity from rat whole kidney is described. Polymorphonuclear leukocyte (PMN) infiltration into tissue is a hallmark of acute inflammation. Historically, the degree of inflammation has been quantified by the identification and enumeration of PMNs histologically or by some other means. More recently, the enzyme activity of MPO, a marker enzyme for PMN, and freshly emigrated monocytes in many inflamed tissues has replaced these methods. The kidney, however, has been identified as a tissue from which MPO cannot be measured. Indeed, kidney homogenized by a standard extraction procedure was devoid of MPO activity. We modified the established methodology so that kidney was homogenized in 5 mM potassium phosphate buffer (PB) first and then centrifuged at 30,000 <em>g</em> for 30 min at 4°C prior to extraction. The resulting 30,000 <em>g</em> pellets expressed MPO activity after suspending them in 50 mM PB containing 0.5% hexadecyltrimethylammoniumbromide (HTAB). Interference in the assay was observed with supernatants from control and inflamed kidney, which appeared to be due to kidney-derived material forming a complex with HTAB. After washing the pellets twice, we noted that their extracts exhibited greater activity, and interference from supernatants was abolished. Using this method, we observed that acutely inflamed kidneys from rats treated with sheep nephrotoxic immunoglobulin G (IgC) had significantly elevated MPO activity over kidneys from control rats. Thus, the described technique allows for the routine assay of MPO in kidney tissue.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 285-295"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90013-B","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13121708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microwave irradiation is effective in the rapid fixation of gastric mucosa for determination of the prostaglandin content","authors":"Fusao Ueda,&nbsp;Masayoshi Watanabe,&nbsp;Yoshihisa Hiratai,&nbsp;Kiyoshi Kimura","doi":"10.1016/0160-5402(90)90012-A","DOIUrl":"10.1016/0160-5402(90)90012-A","url":null,"abstract":"<div><p>The gastric mucosal content of prostaglandin (PC) E₂, 6-keto PGf₁ α, and thromboxane (TX) B₂ was determined by radioimmunoassay in unfed rats. The stomach was removed, and gastric mucosal specimens were prepared by microwave irradiation of the 1) intact stomach, 2) frozen stomach, 3) separated frozen glandular portion, 4) frozen gastric mucosa separated from the stomach wall, and 5) separation of frozen gastric mucosa with no microwave irradiation. Procedure 1 resulted in PGE₂, TXB₂, and 6-keto PGF₁ α levels of 0.75, 2.33, and 3.04 ng/g tissue in the fundus, and 0.33, 1.92, and 1.76 ng/g tissue in the antrum, respectively. In procedures 2–4 these values were much higher, indicating that the PG content of the gastric mucosa is liable to be changed by various artificial procedures, such as freezing and surgical and mechanical handling. In procedure 5, values of PG contents were quite unreliable. These results suggest that microwave irradiation immediately after removal of the stomach may be the most reliable procedure for the accurate determination of the PG content of the gastric mucosa in vivo.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 277-284"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90012-A","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13443559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of lithium in rat brain regions and synaptosomes by graphite furnace atomic absorption spectrophotometry","authors":"Camilo Ríos,&nbsp;Rocío Cuzmán-Méndez","doi":"10.1016/0160-5402(90)90016-E","DOIUrl":"10.1016/0160-5402(90)90016-E","url":null,"abstract":"<div><p>A graphite furnace atomic absorption spectrophotometric method for the analysis of very low concentrations of lithium in brain tissue and subcellular fractions is described. The method has a picogram sensitivity and shows a precision value of 10.1% expressed as the per cent variation coefficient for the tissue analysis of the metal. Lithium concentration in eight regions of the rat brain and regional synaptosomal lithium contents were analyzed with the method described. Results from these determinations show that lithium is heterogeneously distributed among rat brain regions 24 hr after a single s.c. lithium administration; hypothalamus, corpus striatum and midbrain were the regions with the highest lithium accumulation. Lithium is homogeneously concentrated in the synaptosomes obtained from rat brain regions. The method proposed may be considered adequate for trace lithium analysis in pharmacological studies of the metal.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 4","pages":"Pages 327-332"},"PeriodicalIF":0.0,"publicationDate":"1990-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90016-E","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13443565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of gastroduodenal alkaline responses in the rat","authors":"Koji Takeuchi,&nbsp;Hiromichi Niida,&nbsp;Koji Ueshima,&nbsp;Susumu Okabe","doi":"10.1016/0160-5402(90)90029-K","DOIUrl":"10.1016/0160-5402(90)90029-K","url":null,"abstract":"<div><p>We set up a new system for measuring the gastroduodenal HCO₃⁻ responses using pH change and potential difference (PD) in the anesthetized rat. The stomach or the proximal duodenum was perfused at the flow rate of 0.7 mL/min with saline (pH 4.5), the pH of the perfusate and PD were continuously monitored, and HCO₃⁻ output was determined by back-titrating the perfusate and by measuring the area of pH change. In the case of the stomach, acid secretion was inhibited by omeprazole (60 mg/kg, i.p.). Output of both pH and HCO₃⁻ in these tissues was significantly increased by intravenous administration of prostaglandin (PGE₂), 16, 16-dimethyl PGE₂, carbachol, and YM-14673 (a thyrotropin-releasing hormone (TRH) analog), whereas the PD responded to these agents by a significant rise in the duodenum and decrease in the stomach. These parameters also responded to physiological stimulation such as mucosal acidification. When the area of pH change caused by various agents was plotted against the net amount of HCO₃⁻ output determined from back-titration, a significant relationship was found between these two factors (<em>r</em> = 0.98). These results indicate that this system using pH change may be useful for quantitative determination of HCO₃⁻ response in the gastroduodenal mucosa.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 3","pages":"Pages 189-202"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90029-K","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13230592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitive assays for the determination of monoamine oxidase and phenol sulphotransferase activity in small tissue samples","authors":"M.K. Sim,&nbsp;T.P. Hsu","doi":"10.1016/0160-5402(90)90026-H","DOIUrl":"10.1016/0160-5402(90)90026-H","url":null,"abstract":"<div><p>A method to assay phenol Sulphotransferase (PST) and monoamine oxidase (MAO) in brain (anterior pituitary gland, hypothalamus) and liver specimens as small as 4 mg is described. The specimens were homogenized (sonicated) in various volumes of a buffer, the smallest being 100 μL, to obtain the homogenates. MAO assay was carried out using 30 μL of the homogenate and for PST assay, 30 μL of either the homogenate or, in the case of liver, the supernatant (100,000 × g for 60 min). The radiolabeled products of the enzymatic reactions were separated from the radiolabeled substrates by high-pressure liquid chromatography (HPLC) and the radioactivity of the eluted products measured directly by a radioisotope detector coupled to the HPLC system. The constraint of the assay protocol was not the weight of the specimens but the volume of buffer used in the preparation of the homogenate. Although 100 μL was a convenient working volume, the tissue can also, with care, be sonicated in a 50 μL buffer. With extremely small specimens, weighed fractions of the specimens could be sonicated directly in the control and experimental incubation mixtures bypassing the preparation of the homogenate. Thus, the overall method offers, for the first time, a reliable and adaptable means for measuring MAO and PST in small to extremely small tissue specimens.</p></div>","PeriodicalId":16819,"journal":{"name":"Journal of pharmacological methods","volume":"24 3","pages":"Pages 157-163"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0160-5402(90)90026-H","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"13230789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}