geoscience.net logo
+ Resolve Article
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter

+ Translate
+ Subscribe to Site Feed
GeoScience Most Shared ContentMost Shared Content

Effects of noradrenaline and isoprenaline, in combination with - and -receptor blocking substances, on the action potential of cardiac Purkinje fibres


, : Effects of noradrenaline and isoprenaline, in combination with - and -receptor blocking substances, on the action potential of cardiac Purkinje fibres. Journal of Physiology 229(1): 99-113

1. The effects of noradrenaline and isoprenaline on the repolarization phase of the action potential have been studied in the Purkinje fibres of sheep heart, electrically driven at constant rates.2. Isoprenaline (2, 5 and 8 x 10(-8) g/ml.) increases the slope of phase 2 of repolarization and decreases the plateau length; the resulting decrease in action potential duration is concentration dependent, but not rate dependent.3. The effect of isoprenaline on the action potential duration is entirely blocked by propranolol (10(-7) g/ml.) and unaffected by phentolamine (5 x 10(-7) g/ml.).4. In phentolamine (5 x 10(-7) g/ml.) pretreated preparations the response induced by noradrenaline (5 x 10(-8), 1 and 5 x 10(-7) g/ml.) is very similar to that induced by isoprenaline.5. In propranolol (2.5 x 10(-7) g/ml.) pretreated preparations noradrenaline causes a lengthening of the plateau phase and an increase in action potential duration.6. The relationship of these results to the presence of both alpha- and beta-receptors in cardiac Purkinje fibres is discussed.

US$29.90

PMID: 4689996


Other references

Ferrín, G.; Aguilar-Melero, P.; Rodríguez-Perálvarez, M.; Montero-Álvarez, Jé.Luis.; de la Mata, M., 2015: Biomarkers for hepatocellular carcinoma: diagnostic and therapeutic utility. Because of the high prevalence and associated-mortality of hepatocellular carcinoma (HCC), early diagnosis of the disease is vital for patient survival. In this regard, tumor size is one of the two main prognostic factors for surgical resection, w...

Hayashi, K.; Nakazawa, T.; Ohara, H.; Ando, T.; Takada, H.; Tanaka, H.; Sasaki, M.; Kataoka, H.; Nakao, H.; Joh, T., 2008: Autoimmune sclerosing cholangiopancreatitis with little pancreatic involvements by imaging findings. Autoimmune pancreatitis is frequently associated with sclerosing cholangitis. A first clue for suspecting a case of autoimmune pancreatitis is enlargement of the pancreas. We encountered several sclerosing cholangitis cases within a short period,...

Hubbard R.W.; Lau B.; Sanchez A.; Nilsen H.; Gillan W., 1990: Plasma free amino acids in hypercholesterolemic subjects supplemented with nonessential amino acids. FASEB Journal 4(4): A930

Mossa Joann, 1995: Geomorphic effects of the March 1990 flood, northwestern Florida. Abstracts, Annual Meeting - Association of American Geographers 1995: 219

Sabatini, G., 1952: Emetine therapy of paradentosis (pyorrhea alveolaris). Accademia Medica 67(6): 343-348

Bermejo Barrera, P.; Moreda Pineiro, A.; Moreda Pineiro, J.; Bermejo Barrera, A., 1997: Determination of nickel in human scalp hair by slurry sampling-electrothermal atomic absorption spectrometry. The slurry sampling technique has been effective for the determination of nickel in human scalp hair. Hair samples were pulverized using a zirconia vibrational mill ball for 20 min. The powdered samples (0.1 g) were suspended in water and diluted...

Yang, Q.Y.; Li, J.H.; Wang, Q.Y.; Wu, Y.; Qin, J.L.; Cheng, J.J.; Qiu, J., 2015: MTA1 promotes cell proliferation via DNA damage repair in epithelial ovarian cancer. We examined whether metastasis-associated gene 1 (MTA1) promotes cell proliferation via DNA damage repair in ovarian cancer. MTA1 was successfully down-regulated using small interfering RNA in the epithelial ovarian cancer cell lines SKOV-3 and OV...

Abdel-Malak, G.C.rreau, S.T.ibier, M.D.osdowsky, M., 1982: Androgen-binding protein in the seminal plasma of the postpubertal bull. Annals of the New York Academy of Sciences83(383): 479-480

Kermanshai, R.M.carry, B.; Rosenfeld, J.S.mmers, P.; Weretilnyk, E.; Sorger, G., 2001: Benzyl isothiocyanate is the chief or sole anthelmintic in papaya seed extracts. Papaya (Carica papaya) seeds were extracted in an aqueous buffer or in organic solvents, fractionated by chromatography on silica and aliquots tested for anthelmintic activity by viability assays using Caenorhabditis elegans. For all preparations...

King A.R.; Dickinson R.G., 1991: Studies on the reactivity of acyl glucuronides phenolic glucuronidation of isomers of diflunisal acyl glucuronide in the rat. Diflunisal (DF) is metabolized primarily to its acyl glucuronide (DAG), phenolic glucuronide (DPG) and sulphate (DS) conjugates. Whereas DPG and DS are stable at physiological pH, DAG is unstable, undergoing hydrolysis (regeneration of DF) and rea...