Ca2+ pumps in smooth muscle cells

Raeymaekers, Luc; Wuytack, Frank

doi:10.1007/bf00115449

Cited by 35 publications

(8 citation statements)

References 130 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Also, the SR volume of smooth muscle cells, at least in the uterus, is increased by estrogen and during pregnancy (Shoenberg, 1958;Ross and Klebanoff, 1971). Thus, proliferative, developing smooth muscle cells tend to have more SR (Campbell et al, 1971), as is the case for some injured and hypertensive vascular smooth muscle cells (Raeymaekers and Wuytack, 1993).…”

Section: B Sarcoplasmic Reticulummentioning

confidence: 90%

“…Notable among these are active processes such as Ca 2ϩ extrusion across the plasma membrane into the extracellular reservoir by the plasma membrane Ca 2ϩ -ATPase pump (PMCA) and also accumulation of the ion into the SR by the SERCA. Although these two pumps essentially accomplish the same effect of rapidly reducing [Ca 2ϩ ] cyt levels, they have different physicochemical properties and regulatory mechanisms (Grover and Khan, 1992;Raeymaekers and Wuytack, 1993). Using indirect methods in a large vein, Nazer and van Breemen (1998) concluded that nearly half the cytoplasmic free Ca 2ϩ load is extruded via the PMCA, with an equal role for the SERCA and the plasma membrane Na ϩ -Ca 2ϩ exchanger in removal of the remainder.…”

Section: B Sarcoplasmic Reticulummentioning

confidence: 99%

See 1 more Smart Citation

Pharmacological Modulation of Sarcoplasmic Reticulum Function in Smooth Muscle

2004

View full text Add to dashboard Cite

Section: B Sarcoplasmic Reticulummentioning

confidence: 90%

Section: B Sarcoplasmic Reticulummentioning

confidence: 99%

Pharmacological Modulation of Sarcoplasmic Reticulum Function in Smooth Muscle

2004

View full text Add to dashboard Cite

“…Conversely, to enable relaxation, cytosolic calcium levels are lowered by the activity of plasma membrane calcium ATPase (PMCA), sodium/calcium (Na/Ca) exchange, and SR Ca ATPases (SERCA). Two splice variants of SERCA 2, SER-CA 2a and 2b, have been described in vascular smooth muscle, although SERCA 2a is predominately found in heart and skeletal muscle [3]. Another isoform, SERCA 3, is believed to be associated with epithelial and endothelial cells [4].…”

Section: Introductionmentioning

confidence: 98%

Calcium Homeostatic Pathways Change with Gestation in Human Myometrium1

Tribe

Moriarty

Poston

2000

Biology of Reproduction

View full text Add to dashboard Cite

A rise in intracellular calcium is the primary trigger for contractile activity in pregnant human myometrium. It is hypothesized that key proteins involved in myometrial calcium homeostasis are gestationally regulated and play an important role in the preparation for labor. The aims of the study were to investigate the role of sarcoplasmic reticulum Ca ATPases (SERCAs) in regulating spontaneous contractile activity in myometrium, and to determine the expression of SERCA isoforms 2a and 2b, and the plasma membrane Ca ATPase (PMCA), at term and during labor. Western blot analysis demonstrated that the expression of SERCA 2a and 2b significantly increased in myometrium of women in labor compared with those not in labor. The augmentation of contractile activity in laboring myometrium in the presence of a SERCA 2 inhibitor, cyclopiazonic acid (CPA), demonstrated the functional significance of this observation. It is interesting that the application of CPA in the presence of a calcium-activated potassium channel inhibitor to term nonlabor myometrium mimicked the response of myometrium from women in active labor to CPA alone. We conclude that the activity of SERCA isoforms becomes increasingly important in the maintenance of regular contractile activity during labor and may compensate for the functional loss of other calcium control pathways at term.

show abstract

“…Others have presented evidence that the sarcoplasmic reticulum can act as an intracellular sink, removing Ca 2+ from the cytoplasm rather than releasing it. Ca 2+ uptake is obviously a necessary feature of any store if it is to refill after a depleting stimulus, and this refilling depends on the sarcoplasmic reticulum Ca 2+ -ATPase [28]. This ion pump may contribute to the declining phase of the Ca 2+ transient after excitation, speeding the return to resting [Ca 2+ ] i levels and promoting cell relaxation [25].…”

Section: Introductionmentioning

confidence: 99%

Ca2+ uptake by the sarcoplasmic reticulum decreases the amplitude of depolarization-dependent [Ca2+]i transients in rat gastric myocytes

White

McGeown

2000

Pflugers Arch - Eur J Physiol

View full text Add to dashboard Cite

Gastric myocytes loaded with fura-2 were voltage-clamped at -60 mV. Depolarizations to 0 mV evoked nifedipine-sensitive (5 microM) inward currents and Ca2+ transients. Cyclopiazonic acid (5 microM) elevated steady-state [Ca2+]i and reduced Ca current (ICa), but when divalent cations were omitted from the extracellular solution, cyclopiazonic acid had no effect on either the amplitude or the current-voltage relationship of the nifedipine-sensitive current. This suggests that the reduction in ICa was caused by the rise in steady-state [Ca2+]i. The relationship between the total Ca2+ influx carried by the Ca2+ current (sigmaI(Ca).dt) and the amplitude of the Ca2+ transient (delta[Ca2+]i) was analysed for experiments using physiological Ca2+ solutions by calculating the ratio delta[Ca2+]i/sigmaI(Ca).dt. Cyclopiazonic acid (5 microM) and ryanodine (10 microM) both increased this ratio, indicating a decrease in the buffering power of the cell. Mimicking the increase in steady-state [Ca2+]i produced by these agents by changing the holding potential to -40 mV, however, did not affect delta[Ca2+]i/sigmaI(Ca).dt. It was concluded that up-take by a ryanodine-sensitive store normally limits Ca2+ distribution to the bulk cytoplasm following entry to the cell through dihydropyridine-sensitive channels.

show abstract

Ca2+ pumps in smooth muscle cells

Cited by 35 publications

References 130 publications

Pharmacological Modulation of Sarcoplasmic Reticulum Function in Smooth Muscle

Pharmacological Modulation of Sarcoplasmic Reticulum Function in Smooth Muscle

Calcium Homeostatic Pathways Change with Gestation in Human Myometrium1

Ca2+ uptake by the sarcoplasmic reticulum decreases the amplitude of depolarization-dependent [Ca2+]i transients in rat gastric myocytes

Contact Info

Product

Resources

About