Calcium entry and calcium entry blockade

Godfraind, Théophile; Miller, Rc.

doi:10.1016/0143-4160(84)90070-8

Cited by 365 publications

(483 citation statements)

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“…To elucidate whether the spasmolytic effect of the extract is also mediated through the Ca +2 channels blockade, its extract was tested on K + (80 mM)-induced contractions which is known to cause smooth muscles contractions through opening of the voltage dependent L-type Ca +2 channels, thus allowing the influx of extracellular Ca +2 causing a contractile effect (Bolton, 1979) and substances inhibiting the K + (80 mM)-induced contraction are known as Ca +2 channels blockers, i.e., inhibitor of Ca +2 influx (Godfraind et al, 1986;Okumura et al, 1993;Shah et al, 2011). Crude extract of B. wallichiana, like verapamil (standard calcium channel blocker), relaxed the K + (80 mM)-induced contractions, indicating the Ca +2 channel blocking action.…”

Section: Discussionmentioning

confidence: 99%

Pharmacological basis for the folkloric uses of Buxus wallichiana in gastrointestinal, respiratory and vascular disorders

Hussain

Raza

Janbaz

2015

Bangladesh J Pharmacol

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In vitro study was carried out to explore the pharmacological basis of crude extract of Buxus wallichiana for its folkloric uses in gastrointestinal, respiratory and vascular disorders. In jejunum preparations, crude extract (0.03 ± 1.0 mg/mL) caused a transient spasmogenic effect followed by the spasmolytic effect at higher doses (3.0–10 mg/mL). In atropinized jejunum preparation, crude extract inhibited the spontaneous and K+ (80 mM)-induced contraction, suggesting that spasmolytic effect is mediated through the Ca+2-channel blockade. The Ca+2-channel blockade effect was confirmed when pretreatment of tissue with extract produced a dose-dependent shift in Ca+2 concentration-response curves to the right, similarly as verapamil. Furthermore, crude extract exhibited non-specific relaxant effect on carbachol- (1 µM) and K+ (80 mM)-induced tracheal contractions, suggesting the coexistence of anticholi-nergic and Ca+2-antagonistic properties. Moreover, it relaxed the K+ (80 mM)- and phenylephrine (1 µM)-induced contraction in rabbit aorta, suggesting the Ca+2-channel blockade. These findings may validate the folkloric uses of B. wallichiana in constipation, bronchitis, asthma and hypertension.

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Section: Discussionmentioning

confidence: 99%

Pharmacological basis for the folkloric uses of Buxus wallichiana in gastrointestinal, respiratory and vascular disorders

Hussain

Raza

Janbaz

2015

Bangladesh J Pharmacol

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“…For comparison, we characterised the effect of the Ca 2+ channel blocker verapamil [28] on the cationic response to high extracellular K + (Fig. 7).…”

Section: Effects Of Bpdz 73 Onmentioning

confidence: 99%

A potent diazoxide analogue activating ATP-sensitive K + channels and inhibiting insulin release

Lebrun¹,

Arkhammar

Antoine³

et al. 2000

Diabetologia

127

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“…However, these two types of Ca 2+ channels are functionally not com pletely separated in rat aorta (32,34), and voltage-operated Ca 2+ channel blockers (eg., nitrendipine, nifedipine, verapamil) usually in hibited NE-induced contraction completely (36). Thus, in rat aorta, the contraction in duced by either high K+ or NE was inhibited by protopine.…”

Section: Effects Of Protopine On Camp and Cgmp Formationmentioning

confidence: 86%

Ca2+-Channel Blockade in Rat Thoracic Aorta by Protopine Isolated from Corydalis Tubers.

Ko¹,

Wu²,

Lu³

et al. 1992

Jpn.J.Pharmacol

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ABSTRACT-The pharmacological properties and mechanism of the action of pro topine on isolated rat thoracic aorta were examined. It inhibited norepinephrine (NE, 3 ,uM)-induced tonic contraction in rat thoracic aorta in a concentration-dependent manner (25 100 ,ug/ml). The phasic contraction caused by NE was inhibited only by a high concentration of protopine (100pg/ml). At the plateau of NE-induced tonic contraction, the addition of protopine also caused relaxation. This relaxing effect of protopine was not antagonized by indomethacin (20,uM) or methylene blue (50,UM), and it still existed in denuded rat aorta or in the presence of nifedipine (2 100 ,u M). Protopine also inhibited high potassium (60 mM)-induced, calcium-dependent (0.03 3 mM) contraction of rat aorta in a concentration-dependent manner. Neither cAMP nor cGMP level was changed by protopine. Both the formation of inositol monophos phate caused by NE and the phasic contraction induced by caffeine were also not affected by protopine. 45Ca2+ influx caused by either NE or K+ was inhibited by protopine concentration-dependently. It is concluded that protopine relaxed the rat thoracic aorta mainly by suppressing the Ca 2+ influx through both voltage and receptor-operated calcium channels. Chemical structure of protopine.

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Calcium entry and calcium entry blockade

Cited by 365 publications

References 0 publications

Pharmacological basis for the folkloric uses of <i>Buxus wallichiana</i> in gastrointestinal, respiratory and vascular disorders

Pharmacological basis for the folkloric uses of <i>Buxus wallichiana</i> in gastrointestinal, respiratory and vascular disorders

A potent diazoxide analogue activating ATP-sensitive K + channels and inhibiting insulin release

Ca2+-Channel Blockade in Rat Thoracic Aorta by Protopine Isolated from Corydalis Tubers.

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