Specific binding of the calcium antagonist [3H]verapamil to membrane fractions from plants.

Andrejauskas, Elisabeth; Hertel, Rainer; Marmé, Dieter

doi:10.1016/s0021-9258(18)89037-8

Cited by 88 publications

(11 citation statements)

References 19 publications

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“…(1990) for review). Inhibition of ABA-induced stomatal closure by EGTA and chemicals that are known to block Ca2+-channel activity in animals (Nayler 1988), which bind to isolated plant membranes (Andrejauskas et al 1985(Andrejauskas et al , 1986) and which appear only to effect Ca2+-channels in plants may, on first consideration, seem to suggest an apoplastic origin for the ABA-induced increase in [Ca2+]cyt. However, the different sensitivities of Ca2+channels in animal and plant systems (Tester & MacRobbie 1990) necessitate care when assigning direct cause-and-effect relations to these chemicals.…”

Section: Discussionmentioning

confidence: 99%

“…The substantial inhibition observed with (+ ) verapamil might be expected if Ca2+ influx from the apoplast is involved in the ABA response. Verapamil is known to inhibit 45Ca2+ fluxes in plants (Zherelova et al 1985;Tsutsui et al 1987;Graziana et al 1988;Zherelova 1989), and the binding of verapamil to plant membranes (Andrejauskas et al 1985(Andrejauskas et al , 1986Graziana et al 1988; and to membrane proteins (Harvey et al 1989) that exhibit Ca2+-channel activity (Tester & Harvey 1989) has been clearly demonstrated. Similarly, the lesser effects of diltiazem are consistent with the results of earlier studies on Nitellopsis (Shiina & Tazawa 1987) and microsomes and carrot protoplasts (Graziana et al 1988) in which there was no effect on 45Ca2+ entry and in which binding to microsomes was only detected at low ionic concentrations.…”

Section: Discussionmentioning

confidence: 99%

“…Examples from three major groups of Ca2+channel blockers, diltiazem (a benzothiazepine), nifedipine (a dihydropyridine) and verapamil (a phenylalkylamine), are discussed. It has previously been established that these compounds bind to isolated plant membranes (Hetherington & Trewavas 1984;Andrejauskas et al 1985Andrejauskas et al , 1986Dolle & Nultsch 1988a, b) and will also inhibit the entry of 45Ca2+ into carrot protoplasts (Graziana et al 1988). In addition, a verapamil-binding protein has been partly purified from higher plants (Harvey et al 1989) which when reconstituted into planar lipid bilayers exhibits Ca2+channel activity (Tester & Harvey 1989).…”

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confidence: 99%

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Partial inhibition of ABA-induced stomatal closure by calcium-channel blockers

McAinsh

Brownlee

Hetherington³

1991

Proc. R. Soc. Lond. B

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ABA-induced increases in [Ca2+]cyt (cytosolic free Ca2+) may result from Ca2+ influx from the apoplast and/or release from intracellular stores. In this paper, Ca2+-channel blockers have been used to investigate this question in the detached epidermis of Commelina communis. Examples from the benzothiazepine, dihydropyridine and phenylalkylamine series all inhibited ABA-induced stomatal closure: (+ ) verapamil > nifedipine > diltiazem. Inhibition was partial, the magnitude of the effect being dependent on both the concentration of ABA and that of the channel blocker. The maximum inhibition observed in the presence of 100 nM ABA was approximately 66% at high (100 nM) concentrations of ( + ) verapamil or nifedipine. In the near absence of extracellular Ca2+ (2 mM EGTA) ABA-induced stomatal closure was reduced by approximately 22 % and the inhibition by Ca2+-channel blockers abolished. Inhibition by ( + ) verapamil was totally reversible and exhibited signs of stereospecificity, the s( -) enantiomer being a more potent inhibitor of ABA-induced stomatal closure than the r ( + ) enantiomer. Bay K 8644 (a fluorinated analogue of nifedipine) exhibited biphasic action on 500 p,M Ca2+-induced stomatal closure, i.e. agonistic at low concentrations (10 nM), antagonistic at high concentrations (> 10 nM to 100 |iM), but did not affect ABA-induced stomatal closure. These results suggest that Ca2+ release from intracellular stores may be important in the ABA-induced increase in [Ca2+]cyt associated with stomatal closure. They do not, however, exclude a contribution of Ca2+ influx from the apoplast.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Partial inhibition of ABA-induced stomatal closure by calcium-channel blockers

McAinsh

Brownlee

Hetherington³

1991

Proc. R. Soc. Lond. B

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“…In stamen hair cells of Tradescantia, the effects of nif edipine (Wolniak & Bart 19856), other Ca-channel blockers (Hepler 1985) and Cachannel agonists (Chen & Wolniak 1987) are all indicative of a role for Ca in mitosis. Finally, reports of specific binding of Ca-channel blockers in plant plasma mem branes have appeared (Hetherington & Trewavas 1984;Andrejauskas 1985;Graziana et al 1988). Our observations were made on endosperm cells, the storage tissue of seeds in many higher plants.…”

Section: Introductionmentioning

confidence: 92%

Calcium-activated, voltage-dependent, non-selective cation currents in endosperm plasma membrane from higher plants

Stoeckel

Takeda

1989

Proc. R. Soc. Lond. B

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Single-channel and whole-cell patch-clamp techniques were used to characterize the electrophysiological behaviour of plasma membranes from freshly isolated, non-enzyme-treated endosperm protoplasts. A non-selective monovalent cation channel with a single-channel conductance of 22 pS in solutions with physiological potassium concentrations was observed in inside-out patches. The channel passes outward current at depolarized potentials and is highly selective for cations over anions, but discriminates poorly between lithium, sodium, potassium, rubidium and caesium ions. Specific potassium channel blockers were ineffective. The channel kinetics were apparently complex, with burst-like openings and rapid closures within a single burst. Single-channel openings were more frequent both for depolarizing pulses and maintained positive potentials. Channel activity was also increased by elevated cytoplasmic concentrations of either calcium or barium. Subsequent exposure of patches to low calcium, EGTA-buffered solutions resulted in large decreases in activity. Under whole-cell current clamp, small negative resting potentials were observed. A slowly developing outward current evoked by depolarizing pulses was seen in whole-cell recordings.

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“…However, the relative affinity is very low in plants (com pared to anim als) and hence raises questions about the speci ficity of the ligands. For exam ple, although there are d ata which suggest that the verapam il class of cal cium -channel antagonist binds specifically to isolated plant m em branes, there are no obvious binding sites for dihydropyridines in zucchini, corn and carrot m em branes (Andrejauskas et al 1985;G razian a et al 1988), whereas both sites are allosterically coupled in skeletal and cardiac muscles (Glossman & Striessnig 1990). M oreover, it is ap p a ren t th at antibodies raised against anim al channels fail to cross-react with plant m em brane preparations (G raziana et al 1988).…”

Section: (B) a Pproaches To The P U Rifica Tio N O F Calcium Channels F R O M P La N T P La Sm A -M E M B Ra N Ementioning

confidence: 99%

The biochemistry and pharmacology of plasma-membrane calcium channels in plants

Hetherington¹,

Graziana

Mazars

et al. 1992

Phil. Trans. R. Soc. Lond. B

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A review of plasma-membrane calcium channels in higher plants is presented. Data from pharmacological and biochemical studies are used to assess the current state of our knowledge concerning the occurrence of these structures in higher plants. Recent results demonstrate that after purification and reconstitution a phenylalkylamine binding protein will form calcium permeable channels. This result suggests that plants contain structures with some analogy to animal calcium channels. We also suggest that a degree of caution should be observed in the interpretation of results gained in pharmacological studies employing calcium channel active drugs, as it is now clear that even at low doses these com pounds have non-specific effects.

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Specific binding of the calcium antagonist [3H]verapamil to membrane fractions from plants.

Cited by 88 publications

References 19 publications

Partial inhibition of ABA-induced stomatal closure by calcium-channel blockers

Partial inhibition of ABA-induced stomatal closure by calcium-channel blockers

Calcium-activated, voltage-dependent, non-selective cation currents in endosperm plasma membrane from higher plants

The biochemistry and pharmacology of plasma-membrane calcium channels in plants

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