Browsing by Issue Date, starting with "1993"
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- A study of glaucine-induced relaxation of rat aortaPublication . Verde, Ignacio; Orallo, Francisco; Loza, Isabel; Gil-Longo, José; Calleja, José Maria; Cadavid, IsabelThe vasorelaxant effect of glaucine, the major alkaloid of Platycapnos spicata (L.) Bernh., was studied. At concentrations of 10 microM-0.3 mM in normal Krebs solution it was almost equieffective in relaxing K(+)-induced and noradrenaline-induced tension in rat aortic rings without endothelium, with IC50 values of 160 +/- 16 microM and 90 +/- 14 microM respectively. In experiments in a calcium-free medium, 10 microM glaucine strongly inhibited noradrenaline-induced contractions. Glaucine (0.3 mM) did not affect basal uptake of 45Ca, but induced uptake was reduced to 100% (K+) and 97.7% (noradrenaline) of the basal value. These results suggest that glaucine has an intracellular effect and also acts on the cell membrane by blocking voltage-dependent and receptor-operated calcium channels.
- Ionic interactions in phosphate aqueous solutionsPublication . Ferra, Maria Isabel Almeida; Amaro, Albertina; Mendonça, AntónioMean activity coefficients of NaCl have been calculated, by means of the Pitzer theory,in mixed solutions of NaCl and NaH2PO4 and of NaCl and Na2HPO4, with ionic strength lower than 2 mol kg-1, at 25 ºC. Electromotive force measurements, using a silver, silver chloride and a sodium ion selective electrodes, show nernstian response, in those mixed electrolyte solutions.
- Pyridazine derivatives. XI: Antihypertensive activity of 3-hydrazinocycloheptyl[1,2-C]pyridazine and its hydrazone derivativesPublication . Gil-Longo, José; Laguna, Maria de los Reyes; Verde, Ignacio; Castro, Elena; Orallo, Francisco; Fontenla, Jose A.; Calleja, José Maria; Ravina, Enrique; Terán, Carmen3-Hydrazinocycloheptyl[1,2-c]pyridazine (4) and its hydrazone derivatives 3-[N1-(isopropylidene)]hydrazinocycloheptyl[1,2-c]pyridazine [correction of hydrazinocyclohexyl] (5) and 3-[N1-(isobutylidene)]hydrazinocycloheptyl[1,2-c]pyridazine (6) were prepared, and their activity against genetic, neurogenically-induced, and deoxycorticosterone acetate -NaCl-induced hypertension was found to be at least as great as that of hydralazine. The results of studying vasorelaxation of rat aorta by 4 and hydralazine suggest that both these compounds owe their antihypertensive activity to direct relaxation of vascular smooth muscle.
- Antiserotoninergic activity of 2-aminoethylbenzocyclanones in rat aorta: Structure-activity RelationshipsPublication . Verde, Ignacio; Loza, Isabel; Ferreiro, T. G.; Sanz, F.; Lozoya, E.; Rodriguez, J.; Manaut, F.; Castro, Elena; Fontenla, José Angel; Cadavid, Isabel; Honrubia, M.; Fueyo, J.; Ravina, EnriqueSubcellular targeting of the components of the cAMPdependent pathway is thought to be essential for intracellular signaling. Here we have identified a novel protein, named myomegalin, that interacts with the cyclic nucleotide phosphodiesterase PDE4D, thereby targeting it to particulate structures. Myomegalin is a large 2,324-amino acid protein mostly composed of a-helical and coiled-coil structures, with domains shared with microtubule-associated proteins, and a leucine zipper identical to that found in the Drosophila centrosomin. Transcripts of 7.5–8 kilobases were present in most tissues, whereas a short mRNA of 2.4 kilobases was detected only in rat testis. A third splicing variant was expressed predominantly in rat heart. Antibodies against the deduced sequence recognized particulate myomegalin proteins of 62 kDa in testis and 230–250 kDa in heart and skeletal muscle. Immunocytochemistry and transfection studies demonstrate colocalization of PDE4D and myomegalin in the Golgi/centrosomal area of cultured cells, and in sarcomeric structures of skeletal muscle. Myomegalin expressed in COS-7 cells coimmunoprecipitated with PDE4D3 and sequestered it to particulate structures. These findings indicate that myomegalin is a novel protein that functions as an anchor to localize components of the cAMP-dependent pathway to the Golgi/centrosomal region of the cell.
- Δ8 Labdanes from Halimium VerticillatumPublication . Urones, J. G.; Marcos, I. S.; Moro, R. F.; López Rodilla, Jesus Miguel; Mendonça, António José Geraldes deThree new acids in the form of methyl esters and the acetyl derivative of an alcohol have been isolated from Halimium verticillatum. Their structures have been established by spectroscopic methods and/or chemical correlations as those of methyl 15hydroxy-7-oxo-8-labden-17-oate, methyl 7a,l5-dihydroxy-glabden-17-oate, methyl 7/3,15-dihydroxy-8-labden-17-oate and 17-nor-15acetoxy-7-oxo-8-labdene.