+ Site Statistics
+ Resolve Accession
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
Submit PDF Full TextSubmit PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Electrophysiological study of the 2 main pacemaker mechanisms in the rabbit sinus node

, : Electrophysiological study of the 2 main pacemaker mechanisms in the rabbit sinus node. Cardiovascular Research 19(5): 304-318

By extensively mapping the rabbit sinoatrial node (SA node) area and plateau fibers (B cells) were found in a localized area between the caval border of the crista terminalis and the primary pacemaker area. The electrical characteristics of these plateau fibers were close to those of conducting tissue cells and therefore different from the primary pacemaker cells (A cells). When the SA node was cut in small pieces (0.5 by 0.5 mm), the action potentials of the B cells exhibited a mean amplitude of 80 mV and a rate of rise of the ascending phase strongly depressed by 1.10-5 g .cntdot. ml-1 of tetrodotoxin (TTX). The diastolic deplorization was reduced by about 70% in the presence of 1.5 mmol .cntdot. l-1 of Cs ions (Cs). At this concentration, these ions inhibit mainly the current if (a current activated at potentials more negative than -50 mV). In contrast, the action potentials of the A cells recorded in small pieces never exceeded 60 mV and were either barely sensitive or insensitive to the same concentrations of TTX. Their diastolic depolarization (ranging from -60 to -35 mV) was not affected by concentrations of Cs which strongly depressed the diastolic depolarization of the B cells, even when they were hyperpolarized in the same range of potentials. In the B cells, the pacemaker mechanisms is in great part due to the onset of if while it is due in A cells to another mechanism, very like the decay of iK associated with the onset of isi. Two distinct populations of pacemaker cells are clearly distinguishable in the rabbit SA node area when cut in small pieces. In the intact tissue, areas of gradual transition corresponding to the latent pacemaker cells area are present between these 2 kinds of cells, accompanied by a variable and gradual percentage of the 2 main pacemaker mechanisms.

(PDF 0-2 workdays service)

Order PDF Full Text


Click here to order any other PDF Full Text

Accession: 005349847

PDF Full Text: Submit

Submit PDF Full Text

No spam - Every submission is manually reviewed

Due to poor quality, we do not accept files from Researchgate

Submitted PDF Full Texts will always be free for everyone
(We only charge for PDFs that we need to acquire)

Select a PDF file:

Other references

Benahmed, M.; Omezzine, A.; Chater, S.; Mauduit, C.; Florin, A.; Tabone, E.; Chuzel, F.; Bars, R., 2003: Increased expression and activation in adulthood of caspase-3 and -6 in rat germ cells exposed in utero to flutamide. Toxicological Sciences 72(S-1): 131-132, March

Lampe, P. H. J., 1941: Two cases of chloasma with a discussion of the theoretical bases of applied vitamin-C therapy. Chloasma is a name for a symptomatic melanism which is a morphological and probably an etiological entity. In a case of chloasma thyreoidale, the blood vit. C was less than 0.2 mg % and an intraven. adm. of vit. C produced rapid results. This extr...

Hans, D. B.; Allaoua, S.; Perron, C.; Genton, L. C.; Barada, M.; Delmi, M.; Rizzoli, R.; Pichard, C.; Slosman, D., 2000: Comparison of calcaneus versus radius quantitative ultrasound devices Preliminary results of the hip fracture discrimination study. Journal of Bone & Mineral Research 15(Suppl 1): S528, September

Dost, Uwe., 2005: Bullet point comments on the care and breeding of diverse iguanids Stichpunktartige Bemerkungen zu Pflege und Zucht diverser Iguaniden. Iguana Rundschreiben, 181: 16-24

Allen, William H., 1995: AIDS treatment to use baboon cells. Trying to capitalize on the natural ability of cells from the baboon immune system to combat the AIDS virus, researchers plan soon to transplant purified baboon bone-marrow cells into humans. They hope that the baboon cells will survive long enou...

Coombes, R. Charles; Hughes, Stuart, W. M.; Dowsett, M., 1992: 4-Hydroxyandrostenedione: A new treatment for postmenopausal patients with breast cancer. We have evaluated 4-hydroxyandrostenedione, a specific inhibitor of aromatase, as treatment for breast cancer in a phase I dose-ranging study and a phase II study of the best-tolerated dose. 168 postmenopausal patients with locally advanced and me...

Eriksen, Susanne Havn; Jensen, Bo; Schneider, Ib; Kaasgaard, Svend; Olsen, Jorgen, 1994: Utilization of side-chain precursor for penicillin biosynthesis in a high-producing strain of Penicillium chrysogenum. Utilization of the side-chain precursors phenoxyacetic acid (POA) and phenylacetic acid (PA) for penicillin biosynthesis by Penicillium chrysogenum was studied in shake flasks. Precursor uptake and penicillin production were followed by HPLC analy...

Anonymous, 2012: Rival presence leads to reversible changes in male mate choice of a desert dwelling ungulate. Gregarious animals often face the problem of unintended interception of information by group members, as almost all communicatory interactions occur in a public domain. For example, individuals may observe and copy the choices of others. Male mate...

Morowitz, H. J., 1955: Transcapillary migration of heavy water and thiocyanate ion in the pulmonary circulation of normal sub- jects and patients with congestive heart failure. By rapidly injecting into the afferent pulmonary circulation a mixture of T-1824 dye, D2O, and NaSCN in known proportion and collecting 2 second samples for analysis continuously from the femoral artery during the period of the first circulation,...

Hanzlikova E.; Mencik E., 1974: Sixtieth birthday of Dr. Zdenek Roth. Vestnik Ustredniho Ustavu Geologickeho = Bulletin of the Geological Survey, Prague 49(6): 363-371