| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Laboratoire de Pharmacologie Vasculaire Périnatale, Centre de Recherche, Hôpital Sainte-Justine and Department of Obstetrics and Gynecology, Faculty of Medecine, Université de Montréal, Montréal, Québec, Canada H3T 1C5
The contribution of potassium channels [ATP-sensitive potassium (KATP) and high-conductance calcium-activated potassium (BKCa) channels] in the resistance of aortic rings of term pregnant rats to phenylephrine (Phe), arginine vasopressin (AVP), and KCl was investigated. Concentration-response curves to tetraethylammonium (TEA), a nonselective K+ channel inhibitor, were obtained in the absence or presence of KCl. TEA induced by itself concentration-dependent responses only in aortic rings of nonpregnant rats. These responses to TEA could be modulated in both groups of rings by preincubation with different concentrations of KCl. Concentration-response curves to Phe, AVP, and KCl were obtained in the absence or presence of cromakalim or NS-1619 (KATP and BKCa openers, respectively) and glibenclamide or iberiotoxin (KATP and BKCa inhibitors, respectively). Cromakalim significantly inhibited the responses to the three agonists in a concentration-dependent manner in both groups of rats. Alternatively, in the pregnant group of rats, glibenclamide increased the sensitivity to all three agonists. NS-1619 also inhibited the response to all agonists. With AVP and KCl, its effect was greater in aortic rings of pregnant than nonpregnant rats. Finally, iberiotoxin increased the sensitivity to all three agents. This effect was more important in aortic rings of nonpregnant rats and was accompanied by an increase of the maximal response to Phe and AVP. These results suggest that potassium channels are implicated in the control of basal membrane potential and in the blunted responses to these agents during pregnancy.
adenosine 5'-triphosphate-sensitive potassium channel; high conductance calcium-activated potassium channel; pregnancy; vasoconstriction; phenylephrine; vasopressin; potassium chloride
This article has been cited by other articles:
|
|
 |
|
  K. Auger, A. Beausejour, M. Brochu, and J. St-Louis Increased Na+ intake during gestation in rats is associated with enhanced vascular reactivity and alterations of K+ and Ca2+ function Am J Physiol Heart Circ Physiol, October 1, 2004; 287(4): H1848 - H1856. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Simaan, C. Cadorette, M. Poterek, J. St-Louis, and M. Brochu Calcium channels contribute to the decrease in blood pressure of pregnant rats Am J Physiol Heart Circ Physiol, February 1, 2002; 282(2): H665 - H671. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. R. Rosenfeld, D. N. Cornfield, and T. Roy Ca2+-activated K+ channels modulate basal and E2{beta}-induced rises in uterine blood flow in ovine pregnancy Am J Physiol Heart Circ Physiol, July 1, 2001; 281(1): H422 - H431. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
