Introduction
This is a note only for my own rememberance on “Ivannikov, Maxim V., Mutsuyuki Sugimori, and Rodolfo R. Llinás. “Calcium clearance and its energy requirements in cerebellar neurons.” Cell calcium 47.6 (2010): 507-513.”
Note: “Active transport” is the ATP-consuming transportation of ions from/to intracellular/extracellular by pumps, “Passive transport” is the voltage-dependent transportation of ions through channels.
Results
1. Inhibitor of ATP
1.1 Results on the paper
2 types of ATP inhibitor increased delays by 66±25%, 66±15%.
1.2 Conclusion
ATP production, mainly done via glycolysis process, delays Calcium clearance by 66%.
2. Inhibitor of NCX
It showed almost no delay, which means almost nothing. There are other paths Calcium go through.
Postscript on 2026/1/22: It seems to implicate the passive transport via TRPM family have the considerable contribution to the Calcium clearance.
3. Inhibition of PMCA by La3+
3.1 Results on the paper
It delayed the clearance by 64±21%.
3.2 Discussion & Conclusion
It matches the delay caused by ATP inhibitor. It suggests that PMCA is the dominant active transporter on the Calcium clearance.
Postscript on 2026/1/22: It turned out that La3+ inhibits TRPM family, but since adding La3+ disturbs the voltage, the impact on clearance delay needs further analysis.
4 Discussion & Conclusion (in my opinion)
4.1 Estimation based on above discussion
Based on the results on the paper, the Calcium transport capacity is roughly estimated as Active transport: 40%, Passive transport: 60%.
Postscript on 2026/1/22: Since this estimate is based only on ATP-inhibition result, it stands.
4.2 Model-Elaboration using the knowledge on La3+
Turned out that La3+ inhibits both PMCA and TRPM(Google Gemini conversation here), the estimation turns out to require the further analysis, e.g. the multiple regression analysis.
Table 1.
Disclaimer
I don’t know the methodology on each experimental operation is right or not.
Google Gemini Estimation
Not going along with my estimation, Google Gemini has estimated that Active transportː Over 90%, Passive transportː Approx. 8%. Conversation here.
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