| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Nitric oxide (NO) has been shown to modulate neuropeptide secretion from the posterior pituitary. Here we show that NO activates large-conductance Ca2+-activated K+ (BK) channels in posterior pituitary nerve terminals.
NO, generated either by the photolysis of caged-NO or with chemical donors, irreversibly enhanced the component of whole-terminal K+ current due to BK channels and increased the activity of BK channels in excised patches. NO also inhibited the transient A-current. The time courses of these effects on K+ current were very different; activation of BK channels developed slowly over several minutes whereas inhibition of A-current immediately followed NO uncaging.
Activation of BK channels by NO occurred in the presence of guanylyl cyclase inhibitors and after removal of ATP or GTP from the pipette solution, suggesting a cGMP-independent signalling pathway.
The sulfhydryl alkylating agent N-ethyl maleimide (NEM) increased BK channel activity. Pretreatment with NEM occluded NO activation.
NO activation of BK channels occurred independently of voltage and cytoplasmic Ca2+ concentration. In addition, NO removed the strict Ca2+ requirement for channel activation, rendering channels highly active even at nanomolar Ca2+ levels.
These results suggest that NO, or a reactive nitrogen byproduct, chemically modifies nerve terminal BK channels or a closely associated protein and thereby produces an increase in channel activity. Such activation is likely to inhibit impulse activity in posterior pituitary nerve terminals and this may explain the inhibitory action of NO on secretion.
This article has been cited by other articles:
|
|
 |
|
  Z. Zhang, V. Klyachko, and M. B. Jackson Blockade of phosphodiesterase Type 5 enhances rat neurohypophysial excitability and electrically evoked oxytocin release J. Physiol., October 1, 2007; 584(1): 137 - 147. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. D. Peluffo L-Arginine currents in rat cardiac ventricular myocytes J. Physiol., May 1, 2007; 580(3): 925 - 936. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. F. Rossi and W. H. Beierwaltes Nitric oxide modulation of ETB receptor-induced vasopressin release by rat and mouse hypothalamo-neurohypophyseal explants Am J Physiol Regulatory Integrative Comp Physiol, May 1, 2006; 290(5): R1208 - R1215. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Secondo, A. Pannaccione, M. Cataldi, R. Sirabella, L. Formisano, G. Di Renzo, and L. Annunziato Nitric oxide induces [Ca2+]i oscillations in pituitary GH3 cells: involvement of IDR and ERG K+ currents Am J Physiol Cell Physiol, January 1, 2006; 290(1): C233 - C243. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. D. Gutterman, H. Miura, and Y. Liu Redox Modulation of Vascular Tone: Focus of Potassium Channel Mechanisms of Dilation Arterioscler. Thromb. Vasc. Biol., April 1, 2005; 25(4): 671 - 678. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y.-F. Lin, K. Raab-Graham, Y. N. Jan, and L. Y. Jan NO stimulation of ATP-sensitive potassium channels: Involvement of Ras/mitogen-activated protein kinase pathway and contribution to neuroprotection PNAS, May 18, 2004; 101(20): 7799 - 7804. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 I. L. O. Buxton Regulation of Uterine Function: a Biochemical Conundrum in the Regulation of Smooth Muscle Relaxation Mol. Pharmacol., May 1, 2004; 65(5): 1051 - 1059. [Abstract] [Full Text]
|
|
|
|
|
|
D. K. Mulkey, R. A. Henderson III, N. A. Ritucci, R. W. Putnam, and J. B. Dean Oxidative stress decreases pHi and Na+/H+ exchange and increases excitability of solitary complex neurons from rat brain slices Am J Physiol Cell Physiol, April 1, 2004; 286(4): C940 - C951. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. W. Jacklet and D. G. Tieman Nitric Oxide and Histamine Induce Neuronal Excitability by Blocking Background Currents in Neuron MCC of Aplysia J Neurophysiol, February 1, 2004; 91(2): 656 - 665. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. A. Andric, A. E. Gonzalez-Iglesias, F. Van Goor, M. Tomic, and S. S. Stojilkovic Nitric Oxide Inhibits Prolactin Secretion in Pituitary Cells Downstream of Voltage-Gated Calcium Influx Endocrinology, July 1, 2003; 144(7): 2912 - 2921. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 E. E. Daniel, T. J. Bowes, and J. Jury Roles of Guanylate Cyclase in Responses to Myogenic and Neural Nitric Oxide in Canine Lower Esophageal Sphincter J. Pharmacol. Exp. Ther., June 1, 2002; 301(3): 1111 - 1118. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. L. McLean and K. T. Sillar Nitric Oxide Selectively Tunes Inhibitory Synapses to Modulate Vertebrate Locomotion J. Neurosci., May 15, 2002; 22(10): 4175 - 4184. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Schwingshackl, R. Moqbel, and M. Duszyk Nitric oxide activates ATP-dependent K+ channels in human eosinophils J. Leukoc. Biol., May 1, 2002; 71(5): 807 - 812. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Renganathan, T. R. Cummins, and S. G. Waxman Nitric Oxide Blocks Fast, Slow, and Persistent Na+ Channels in C-Type DRG Neurons by S-Nitrosylation J Neurophysiol, February 1, 2002; 87(2): 761 - 775. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. S. Kostic, S. A. Andric, and S. S. Stojilkovic Spontaneous and Receptor-Controlled Soluble Guanylyl Cyclase Activity in Anterior Pituitary Cells Mol. Endocrinol., June 1, 2001; 15(6): 1010 - 1022. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. P. Ahern, S.-F. Hsu, V. A. Klyachko, and M. B. Jackson Induction of Persistent Sodium Current by Exogenous and Endogenous Nitric Oxide J. Biol. Chem., September 8, 2000; 275(37): 28810 - 28815. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
