Quick stretch increases the production of inositol 1,4,5-trisphosphate (IP3) in porcine coronary artery

Tanaka, Yoshio; Hata, Shinzo; Ishiro, Hiromi; Ishii, Kunio; Nakayama, Koichi

doi:10.1016/0024-3205(94)00884-1

Cited by 29 publications

(20 citation statements)

References 14 publications

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“…15) NCDC (100 mM) also inhibits the production of IP 3 in pig coronary artery stimulated with acetylcholine and mechanical stretch. 16) In general, PLC activity is enhanced with the stimulation of chemical receptors. However, the enzyme activity can be also increased without any chemical receptor stimulations.…”

Section: Discussionmentioning

confidence: 99%

Phospholipase C Inhibitors Suppress Spontaneous Mechanical Activity of Guinea Pig Urinary Bladder Smooth Muscle

Tanaka

Okamoto

Imai

et al. 2003

Biological & Pharmaceutical Bulletin

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Urinary bladder smooth muscle (UBSM) exhibits spontaneous rhythmic contraction. This spontaneous mechanical activity is generated in the presence of neuronal blockade and thus is myogenic in origin. The spontaneous myogenic contraction of UBSM may be the fundamental determinant of the physiological functions of the urinary bladder to store and excrete urine. Although the mechanisms by which UBSM generates spontaneous contraction have not been completely ascertained, its induction has been suggested to be intimately associated with smooth muscle cell action potentials to enhance extracellular Ca(2+) influx through voltage-gated L-type Ca(2+) channels. However, the alteration of membrane electrical activity does not seem to be the exclusive trigger mechanism for the generation of the spontaneous contraction. In the present study, we show that spontaneous mechanical activity of guinea pig UBSM is substantially diminished by an inhibitor of phospholipase C (PLC), U-73122, but is not affected by its inactive form, U-73343. Significant attenuation of the mechanical activity can be also obtained with another PLC inhibitor 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate. Our present findings suggest a significant role for the activation of PLC and subsequent inositol 1,4,5-trisphosphate-induced Ca(2+) release mechanism as an alternative triggering system for inducing spontaneous mechanical activity of UBSM. The present results support the idea that the action potential is not the sole pacemaker mechanism by which spontaneous contraction is induced in UBSM.

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Section: Discussionmentioning

confidence: 99%

Phospholipase C Inhibitors Suppress Spontaneous Mechanical Activity of Guinea Pig Urinary Bladder Smooth Muscle

Tanaka

Okamoto

Imai

et al. 2003

Biological & Pharmaceutical Bulletin

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“…In this case, phospholipase C activation probably plays a role in volume regulation of this wall-less green alga. Mechanical stretching is also reported to increase IP 3 via phospholipase C activation in coronary artery (Tanaka et al, 1994). Thus a stretch-activated phospholipase C is a possible mechanism for sensing hyphal expansion.…”

Section: Comparison With Other Organismsmentioning

confidence: 94%

Calcium gradient dependence of Neurospora crassa hyphal growth

Silverman‐Gavrila

Lew

2003

Microbiology

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A tip-high cytoplasmic calcium gradient has been identified as a requirement for hyphal growth in the fungus Neurospora crassa. The Ca 2+ gradient is less steep compared to wall vesicle, wall incorporation and vesicular Ca 2+ gradients, but this can be explained by Ca 2+ diffusion.Analysis of the relation between the rate of hyphal growth and the spatial distribution of tip-localized calcium indicates that hyphal growth rates depend upon the tip-localized calcium concentration. It is not the steepness of the calcium gradient, but tip-localized calcium and the difference in tip-localized calcium versus subapical calcium concentration which correlate closely with hyphal growth rate. A minimal concentration difference between the apex and subapical region of 30 nM is required for growth to occur. The calcium concentration dependence of growth may relate directly to biochemical functions of calcium in hyphal extension, such as vesicle fusion and enzyme activation during cellular expansion. Initiation of tip growth may rely upon random Ca 2+ motions causing localized regions of elevated calcium. Continued hyphal expansion may activate a stretch-activated phospholipase C which would increase tip-localized inositol 1,4,5-trisphosphate (IP 3 ). Hyphal expansion, induced by mild hypoosmotic treatment, does increase diacylglycerol, the other product of phospholipase C activity. This is consistent with evidence that IP 3 -activated Ca 2+ channels generate and maintain the tip-high calcium gradient.

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“…The production of IP 3 has been demonstrated to be enhanced with mechanical stimulation such as stretch as well as chemical receptor activation in intact muscles such as rat heart muscle and pig coronary artery (Dassouli et al 1993;Tanaka et al 1994). Since urinary bladder is known to have mechano-sensor mechanism(s) for muscle stretch (Fry et al 1998;Wellner and Isenberg 1993), IP 3 production might be enhanced during rhythmic contraction in urinary bladder smooth muscle.…”

Section: Discussionmentioning

confidence: 96%

2-Aminoethoxydiphenyl borate causes dissociation between membrane electrical and mechanical activity in guinea-pig urinary bladder smooth muscle

Imai

Tanaka

Okamoto

et al. 2002

Naunyn-Schmiedeberg's Archives of Pharmacology

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Physiological functions of urinary bladder profoundly reflect smooth muscle mechanical activity. Urinary bladder smooth muscle itself produces myogenic rhythmic contraction, and this spontaneous mechanical event could be the fundamental determinant of urinary bladder functions. The spontaneous contraction of urinary bladder smooth muscle is thought to be triggered primarily by the action potential generated in this smooth muscle cell. Modulators of ion channels contributing to the configuration of action potential also affect urinary bladder smooth muscle mechanical activity as expected exactly from the effects on the electrical event. In the present study, we show that the frequency of action potential recorded in intact strip of guinea-pig urinary bladder smooth muscle is dramatically increased by 2-aminoethoxydiphenyl borate (2-APB; 30 microM) from 0.2 Hz to 1 Hz (approximately 500% increments). In contrast to an increasing effect expected from the membrane electrical alterations, mechanical activity (both contraction amplitude and frequency) of this smooth muscle is unexpectedly reduced by the same concentration of 2-APB to approximately 35% of the control. The present results firstly show an apparent dissociation of electrical-mechanical coupling in urinary bladder smooth muscle. The alteration of membrane electrical activity might not be the exclusive trigger mechanism responsible for the generation of spontaneous rhythmic contraction of this smooth muscle.

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Quick stretch increases the production of inositol 1,4,5-trisphosphate (IP3) in porcine coronary artery

Cited by 29 publications

References 14 publications

Phospholipase C Inhibitors Suppress Spontaneous Mechanical Activity of Guinea Pig Urinary Bladder Smooth Muscle

Phospholipase C Inhibitors Suppress Spontaneous Mechanical Activity of Guinea Pig Urinary Bladder Smooth Muscle

Calcium gradient dependence of Neurospora crassa hyphal growth

2-Aminoethoxydiphenyl borate causes dissociation between membrane electrical and mechanical activity in guinea-pig urinary bladder smooth muscle

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