scholarly journals Local recovery of cardiac calcium‐induced calcium release interrogated by ultra‐effective, two‐photon uncaging of calcium

2021 ◽  
Author(s):  
Radoslav Janicek ◽  
Hitesh Agarwal ◽  
Ana M. Gómez ◽  
Marcel Egger ◽  
Graham C.R. Ellis‐Davies ◽  
...  
2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Natsumi Miyazaki ◽  
Takayuki Kobayashi ◽  
Takako Komiya ◽  
Toshio Okada ◽  
Yusuke Ishida ◽  
...  

Abstract Background Malignant hyperthermia (MH) is a rare genetic disease characterized by the development of very serious symptoms, and hence prompt and appropriate treatment is required. However, postoperative MH is very rare, representing only 1.9% of cases as reported in the North American Malignant Hyperthermia Registry (NAMHR). We report a rare case of a patient who developed sudden postoperative hyperthermia after mastectomy, which was definitively diagnosed as MH by the calcium-induced calcium release rate (CICR) measurement test. Case presentation A 61-year-old Japanese woman with a history of stroke was hospitalized for breast cancer surgery. General anesthesia was introduced by propofol, remifentanil, and rocuronium. After intubation, anesthesia was maintained using propofol and remifentanil, and mastectomy and muscle flap reconstruction surgery was performed and completed without any major problems. After confirming her spontaneous breathing, sugammadex was administered and she was extubated. Thereafter, systemic shivering and masseter spasm appeared, and a rapid increase in body temperature (maximum: 38.9 °C) and end-tidal carbon dioxide (ETCO2) (maximum: 59 mmHg) was noted. We suspected MH and started cooling the body surface of the axilla, cervix, and body trunk, and administered chilled potassium-free fluid and dantrolene. After her body temperature dropped and her shivering improved, dantrolene administration was ended, and finally she was taken to the intensive care unit (ICU). Body cooling was continued within the target range of 36–37 °C in the ICU. No consciousness disorder, hypotension, increased serum potassium level, metabolic acidosis, or cola-colored urine was observed during her ICU stay. Subsequently, her general condition improved and she was discharged on day 12. Muscle biopsy after discharge was performed and provided a definitive diagnosis of MH. Conclusions The occurrence of MH can be life-threatening, but its frequency is very low, and genetic testing and muscle biopsy are required to confirm the diagnosis. On retrospective evaluation using the malignant hyperthermia scale, the present case was almost certainly that of a patient with MH. Prompt recognition and immediate treatment with dantrolene administration and body cooling effectively reversed a potentially fatal syndrome. This was hence a valuable case of a patient with postoperative MH that led to a confirmed diagnosis by CICR.


2012 ◽  
Vol 32 (12) ◽  
pp. 4271-4283 ◽  
Author(s):  
Z. Qin ◽  
X. Zhou ◽  
M. Gomez-Smith ◽  
N. R. Pandey ◽  
K. F. H. Lee ◽  
...  

2008 ◽  
Vol 32 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Willmann Liang

This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled “Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum.” In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In closing, technical issues associated with the skinned cell model are mentioned. Based on this review article, teaching and learning points are put forth in this article to highlight two concepts: 1) the regulatory mechanisms of CICR in cardiomyocytes and 2) the recognition of contradicting hypotheses and limitations in experimental design. The first concept is certainly an important one for physiology students. The second concept is universally applicable to researchers in all fields of science. It is thus the aim of this article to cultivate a rewarding teaching and learning experience for both instructors and students.


2005 ◽  
Vol 288 (4) ◽  
pp. F785-F791 ◽  
Author(s):  
Susan K. Fellner ◽  
William J. Arendshorst

ANG II induces a rise in cytosolic Ca2+ ([Ca2+]i) in vascular smooth muscle (VSM) cells via inositol trisphosphate receptor (IP3R) activation and release of Ca2+ from the sarcoplasmic reticulum (SR). The Ca2+ signal is augmented by calcium-induced calcium release (CICR) and by cyclic adeninediphosphate ribose (cADPR), which sensitizes the ryanodine-sensitive receptor (RyR) to Ca2+ to further amplify CICR. cADPR is synthesized from β-nicotinamide adenine dinucleotide (NAD+) by a membrane-bound bifunctional enzyme, ADPR cyclase. To investigate the possibility that ANG II activates the ADPR cyclase of afferent arterioles, we used inhibitors of the IP3R, RyR, and ADPR cyclase. Afferent arterioles were isolated from rat kidney with the magnetized microsphere and sieving technique and loaded with fura-2 to measure [Ca2+]i. In Ca2+-containing buffer, ANG II increased [Ca2+]i by 125 ± 10 nM. In the presence of the IP3R antagonists TMB-8 and 2-APB, the peak responses to ANG II were reduced by 74 and 81%, respectively. The specific antagonist of cADPR 8-Br ADPR and a high concentration of ryanodine (100 μM) inhibited the ANG II-induced increases in [Ca2+]i by 75 and 69%, respectively. Nicotinamide and Zn2+ are known inhibitors of the VSM ADPR cyclase. Nicotinamide diminished the [Ca2+]i response to ANG II by 66%. In calcium-free buffer, Zn2+ reduced the ANG II response by 68%. Simultaneous blockade of the IP3 and cADPR pathways diminished the [Ca2+]i response to ANG II by 83%. We conclude that ANG II initiates Ca2+ mobilization from the SR in afferent arterioles via the classic IP3R pathway and that ANG II may lead to activation of the ADPR cyclase to form cADPR, which, via its action on the RyR, substantially augments the Ca2+ response.


1995 ◽  
Vol 73 (4) ◽  
pp. 1422-1429 ◽  
Author(s):  
L. Aniksztejn ◽  
M. Sciancalepore ◽  
Y. Ben Ari ◽  
E. Cherubini

1. The single-electrode voltage-clamp technique was used to study the effects of the metabotropic glutamate receptors (mGluRs) agonist 1S,3R-1-aminocyclopentane-1,3-dicarboxylic acid (1S,3R-ACPD, ACPD, 3-10 microM) on CA3 hippocampal neurons during the 1st 10 days of postnatal (P) life and in adulthood. 2. Repeated applications of 1S,3R-ACPD, in the presence of tetrodotoxin (TTX, 1 microM), tetraethylammonium chloride (TEACl 10 mM), and CsCl (2 mM), induced in immature but not in adult neurons periodic inward currents (PICs) that persisted for several hours after the last application of the agonist. 3. PICs, which were generated by nonspecific cationic currents, reversed polarity at 2.8 +/- 3 (SD) mV. They were reversibly blocked by kynurenic acid (1 mM), suggesting that they were mediated by glutamate acting on ionotropic receptors. They were also abolished in a nominally Ca(2+)-free medium. 4. PICs were irreversibly abolished by thapsigargin (10 microM) but were unaffected by ryanodine (10-40 microM). Caffeine (2 mM) also reversibly blocked PICs; this effect was independent from adenosine 3',5'-cyclic monophosphate (cAMP) accumulation, inhibition of voltage-dependent Ca2+ current, or blockade of adenosine receptors. 5. We suggest that, in neonatal slices, mGluRs-induced PICs are triggered by elevation of [Ca2+]i, after mobilization of Ca2+ from inositol 1,4,5-trisphosphate (InsP3)-sensitive stores. This will lead to a persistent, pulsatile release of glutamate from presynaptic nerve terminals, a phenomenon that is probably maintained via a calcium-induced-calcium release process.


1989 ◽  
Vol 94 (2) ◽  
pp. 363-383 ◽  
Author(s):  
M Iino

Fura-2 was used to measure the amount of Ca released from the intracellular Ca store of a saponin-skinned smooth muscle fiber bundle of the guinea pig taenia caeci (width, 150-250 microns) placed in a capillary cuvette at 20-22 degrees C. The amount of Ca actively loaded into the store was assayed when released by the application of 50 mM caffeine and/or 10 microM inositol 1,4,5-trisphosphate (IP3) in the absence of ATP, and was found to have a biphasic dependence on the loading [Ca2+] with a peak near pCa 6. After Ca loading at pCa 6, IP3 released almost all the releasable Ca, whereas caffeine discharged Ca from only approximately 40% of the store. The maximum amount of Ca in the store was some 220 mumol/liter cell water. Ca in the caffeine-releasable store was released approximately exponentially to zero with time when Ca2+ was applied in the absence of ATP, and the rate constant of the Ca-induced Ca release (CICR) increased steeply with the concentration of Ca2+ applied. Increase in [Mg2+] (0.5-5.0 mM) or decrease in pH (7.3-6.7) shifted the relation between pCa and the rate of CICR roughly in parallel toward the lower pCa. An adenine nucleotide increased the rate of the CICR, but it did not change the range of effective [Ca2+]. 5 mM caffeine greatly enhanced the CICR mechanism, making it approximately 30 times more sensitive to [Ca2+]. However the drug had no Ca-releasing action in the absence of Ca2+. Procaine in millimolar concentrations inhibited the rate of the CICR. These properties are similar to those of the skeletal muscle CICR and ryanodine receptor channels. Rates of the CICR under a physiological ionic milieu were estimated from the results, and a [Ca2+] greater than 1 microM was expected to be necessary for the activation of the Ca release. This Ca sensitivity seems too low for the CICR mechanism to play a primary physiological role in Ca mobilization, unless assisted by other mechanisms.


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