Relationship between 3H-ryanodine uptake and myocardial contractility

Fr, Ciofalo

doi:10.1152/ajplegacy.1973.225.2.324

Cited by 15 publications

(19 citation statements)

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“…The protocol used is indicated beneath each set of records. Under control conditions, the amplitude of the PRC 30 was not affected by the conditioning rest as illustrated in the top panel (arrows). However, in the presence of 100 pM ryanodine (lower panel), the amplitude of the PRC30 following the 10-minute conditioning rest was greatly increased compared to that preceding the conditioning rest (arrows).…”

Section: General Effects Of Ryanodinementioning

confidence: 92%

“…A muscle was judged suitable for use if the amplitude of the first twitch elicited on restimulation (post-rest contraction or PRC), expressed as a percent of the prerest steadystate twitch amplitude, was constant within ± 2% when test rest periods of 30 seconds were repeated. The 30-second test rest period (PRC 30 ) was chosen since it usually resulted in maximal rest potentiation under control conditions.…”

Section: Experimental Protocolsmentioning

confidence: 99%

“…In 2 additional preparations, the decay appeared to be a biphasic process (rapid decay followed by a slower one). Figure 3 shows the effect of interposing a long rest period (10 minutes) between 2 test rest periods of 30 seconds (PRC 30 ) on the amplitude of the test PRCs. The protocol used is indicated beneath each set of records.…”

Section: General Effects Of Ryanodinementioning

confidence: 99%

“…Results obtained in a typical preparation are shown in Figure 4. After the twitch had reached the 1 Hz steadystate amplitude after a PRC 30 To quantitate the recovery from ryanodine-induced blockade during rest, conditioning rest periods of 5 seconds to 20 minutes were applied using the protocol shown in Figure 5 (inset). A 3 Hz stimulation period was used to reinduce blockade for each trial rest period.…”

Section: Recovery From and Reinduction Of Blockmentioning

confidence: 99%

“…The recovery of PRC was defined as the ratio of PRC after to that before the conditioning rest (PRC: post/pre). It was assumed that the block removal during the PRC 30 to removal during rest periods longer than 150 seconds. Under control conditions, conditioning rests had no effect on PRC 30 , as indicated by the horizontal line (open circles).…”

Section: Recovery From and Reinduction Of Blockmentioning

confidence: 99%

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Use-dependence of ryanodine effects on postrest contraction in ferret cardiac muscle.

Malécot¹,

Katzung²

1987

Circulation Research

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During an investigation of the effect of ryanodine on contractions in cardiac muscle, it was found that long rest periods removed all or most of the drug's effect. Therefore, we studied the kinetics of block development and recovery from block produced by low concentrations of ryanodine (1-100 pM) on the postrest contractions of ferret papillary muscle. At 100 pM, ryanodine depressed steady-state contraction amplitude slightly (4.2 ± 1.1% mean ± SEM, n = 10) but strongly inhibited (40-80%) the first contraction (postrest contraction) elicited on restimulation of the preparation after rest periods of 1 second to 5 minutes. Under control conditions, the nearly maximal potentiation of the twitch occurring after a standard test rest period (30 seconds of rest) was not affected by a preceding conditioning rest of up to 20 minutes. In the presence of 100 pM ryanodine, a conditioning rest increased the amplitude of the twitch elicited after a test rest, and the test rest contraction recovered toward control (drug-free) amplitude monoexponentially (time constant, 582 ± 105 seconds). Block of postrest contraction could be reinduced by stimulation and occurred faster when higher rates were used (time constants, 758 seconds at 1 Hz and 107 ± 26 seconds at 3 Hz). Since rest potentiation of twitch tension is believed to be mostly dependent on extra calcium released from the sarcoplasmic reticulum, the results suggest that the ryanodine-induced blockade of calcium release from the sarcoplasmic reticulum is use-dependent and recovers during diastole. Such use-dependence might be mediated by modulation of the drug-receptor interaction by intracellular calcium, transsarcolemmal or transsarcoplasmic reticulum membrane potential, or the state of a sarcoplasmic reticulum membrane calcium channel. (Circulation Research 1987;60:560-567)

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Section: General Effects Of Ryanodinementioning

confidence: 92%

Section: Experimental Protocolsmentioning

confidence: 99%

Section: General Effects Of Ryanodinementioning

confidence: 99%

Section: Recovery From and Reinduction Of Blockmentioning

confidence: 99%

Section: Recovery From and Reinduction Of Blockmentioning

confidence: 99%

See 3 more Smart Citations

Use-dependence of ryanodine effects on postrest contraction in ferret cardiac muscle.

Malécot¹,

Katzung²

1987

Circulation Research

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Pharmacology of Calcium Uptake and Release from the Sarcoplasmic Reticulum: Sensitivity to Methylxanthines and Ryanodine

Chapman¹,

Tunstall²

1988

Calcium in Drug Actions

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Effect of ryanodine on myocardial calcium

Frank

Sleator

1975

Naunyn-Schmiedeberg's Arch. Pharmacol.

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The effects of ryanodine and ryanodine steady-state condition (RSSC) on contractile-related calcium were examined in isolated guinea pig left atrial muscle. 1. RSSC is a specific irreversible condition occurring after a brief exposure to 1 x 10(-7) M ryanodine, followed by washing. It is characterized by elimination of the contraction following a 10-sec rest interval (post-rest) and prolongation of the associated action potential duration (AP50%) from 78.9 to 160.8 msec with minimal alteration in steady-state tension development determined at 1 Hz. 2. Induction of RSSC with a ryanodine-bovine serum albumin conjugate produced similar alterations in post-rest contractile strength and action potential duration. 3. In the presence of 1 x 10(-7) M ryanodine, guinea pig left atria exhibit a significant increase in total 45Ca efflux from two rapidly exchangeable compartments (compartment 1, t1/2=1.58 min; compartment 2, t1/2=8.20 min). 4. In atria loaded after the induction of RSSC, total 45Ca release was significantly reduced by 7.2% of the total exchange. 5. The 45Ca exchange space for RSSC atria was reduced from 23.22 +/- 0.81 to 19.85 +/- 1.22 ml per 100 g muscle without a significant reduction in the total exchange space. 6. From these results, it is concluded that the effects of low concentrations of ryanodine and RSSC are to alter the contractile calcium levels of the tissue, primarily from sarcolemmal membrane sites which regulate post-rest contractile strength and action potential duration.

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Relationship between 3H-ryanodine uptake and myocardial contractility

Cited by 15 publications

References 0 publications

Use-dependence of ryanodine effects on postrest contraction in ferret cardiac muscle.

Use-dependence of ryanodine effects on postrest contraction in ferret cardiac muscle.

Pharmacology of Calcium Uptake and Release from the Sarcoplasmic Reticulum: Sensitivity to Methylxanthines and Ryanodine

Effect of ryanodine on myocardial calcium

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