Educational Qualifications

Professional Experience

Training

Achievements

What I consider as key achievements in my research career:

1. Demonstrating that the antiarrhythmic activity of the organic calcium channel blockers verapamil and diltiazem may not be due to calcium channel blockade as currently considered, but due to block of a diastolic calcium leak from cardiac tissue.

Sathya Subramani, Caroline Vijayanand and Elizabeth Tharion. (2002) Differential effects of organic calcium-channel blockers on diastolic SR calcium  handling in the frog heart.  British Journal of Pharmacology, 137: 756-760). [Pubmed]

2. Establishing the molecular mechanism of a physiological concept called the “Bowditch phenomenon” or Force-frequency relation in the heart.

S. Subramani, S. Balakrishnan, T. Jyoti, S. Sathishkumar, A. A. Mohammed, S. Arasan and C. Vijayanand. (2005). Force-frequency relation in frog-ventricle is dependent on the direction of sodium/calcium exchange in diastole.  Acta Physiologica Scandinavica, 185, 193-202. [Pubmed] 

* See Editor’s choice:  Nilsson H. Force-frequency relation and sodium-calcium exchange: moving the staircase. Acta Physiol Scand. 2005 Nov;185(3):169. [Pubmed]

This paper was the editor’s choice in Acta Physiologica Scandinavica. Quoting the editor here: “The mechanism of Bowditch effect…. is still not known in detail, even though Henry Pickering Bowditch first published his observation of the positive force-frequency relation (FFR) in the frog heart in 1871…. The article by Subramani and colleagues in this issue shows that inhibition of calcium channels in the frog heart seems to have little influence, while interventions affecting the transmembrane sodium gradient alter the FFR….  This novel and potentially controversial idea now awaits confirmation from other studies.

3. Demonstrating ( in accordance with the view of Chapman and colleagues) that there is a funtional intracellular calcium store in the frog-ventricle (many researchers believe that there is no intracellular calcium store in frog ventricle).Bhaskar A, Subbanna PK, Arasan S, Rajapathy j, Rao JP and Subramani S. (2008) 4-Aminopyridine-induced contracture in frog ventricle is due to calcium released from intracellular stores. Indian Journal of Physiology and Pharmacology 52 (4); 366-374. [Pubmed] [PDF]

4. Understanding the electrophysiological model of frog skin (it is a good surrogate for mammalian renal epithelium).

Silviya Rajakumari Jared, J. Prakasa Rao and Sathya Subramani. (2009). Actions of antidiuretic hormone analogues on intact and nystatin-permeabilized frog skins. Experimental Physiology 94 (12): 1174-1184. [Pubmed]

In this paper, we have argued that what is called ‘Short circuit current’ in the literature on transepithelial transport in renal epithelia, cannot reflect sodium-potassium pump current. It can only be due to transport across channels. (Many reports treat the short circuit current as arising due to sodium-potassium pump activity). 

5. Establishing experimental and analytical methodology to study ECG, blood pressure, respiration and electrolyte abnormalities in anaesthetized rats, and the successful creation of an animal model of Cleistanthus collinus poisoning (human cases are due to suicidal attempts).

6. Use of the above model to demonstrate that Distal Renal Tubular Acidosis seen in cases of C.collinus poisoning is due to blockade of proton pumps in distal renal tubule. 

Maneksh D, Sidharthan A, Kettimuthu K, Kanthakumar P, Lourthuraj AA, Ramachandran A & Subramani S. Cleistanthus collinus induces type I distal renal tubular acidosis and type II respiratory failure in rats. Indian J Pharmacol. 2010 May;42(3):178-184. [Link] [PDF]

Kettymuthu K, Ramachandran A, Lourthuraj AA, Manickam SA, Subramani S. (2009) Mechanism of toxicity of Cleistanthus collinus: Vacuolar H+ ATPases are a putative target. Clinical Toxicology 47(7): 724.[Link] [PDF]

7. With the same model, we show that DRTA may be incidental, but the cause of death is sudden respiratory arrest due to failure of central respiratory rhythm.

One major occupation in recent times is isolation of active principles from C.collinus leaves using chromatographic methods. We have isolated Diphyllin and Cleistanthin A to single HPLC peak purity for mechanistic studies. The rat model of toxicity that we have developed is being used to test treatment modalities for C.collinus poisoning.

8. Understanding the oxygen-carbon dioxide diagram of Rahn and Fenn and realizing the significance of the alveolar gas equation. 

Subramani S, Kanthakumar P, Maneksh D, Sidharthan A, Rao SV, Parasuraman V and Tharion E. O2-CO2 diagram as a tool for comprehension of blood gas abnormalities. Adv Physiol Edu. 2011 Sep;35(3):314-20. [Pubmed] [PDF]

Awards

• Won the third prize in faculty oral presentation during the Excel and Educate 2025 Future of Medicine International Medical Conference conducted by the Tamil Nadu Dr. MGR Medical University and Department of Health and Family Welfare, Government of Tamil Nadu from October 16-18. 

• Won the best faculty oral presentation prize on 14th December 2024 during the 70th annual national conference of the Association of Physiologists and Pharmacologists of India (APPICON 2024) held at ESIC Medical College, Chennai. 

• Won the second prize in the basic science faculty oral presentation at the 10th Annual Research Day held at Christian Medical College, Vellore 2019.

• Was awarded the honour of delivering the Dr. A. C. Duarte Monteiro Oration on "Septic Shock and Alpha Block" at Seth G. S. Medical College, Mumbai on 7th December 2016.

• Award for the best oral presentation by basic science faculty during the annual CMC research day held on October 10, 2016.

• Was awarded the Robert-Ray Kroc Lectureship by the Dept of Physiology, University of Southern California, Los Angeles, California. The lecture titled “Cardiac arrhythmias and calcium-channel blockers” was given in Jan 2003.

Publications

1. Singh SC, Prince N, Amirtham SM and Subramani S, 2024. Effect of Cleistanthoside A on blood pressure of rats - Can vasoconstrictors help in Cleistanthus collinus poisoning? Indian J Pharmacol 56, 146–147. https://doi.org/10.4103/ijp.ijp_491_23

2. Charles J, Nedumaran L, Raman S, Vinod E, Rajasegaran R, Vadivel K, Bhaskar A and Subramani S, 2024. Rhythm Generating Mechanisms in Rat Sinoatrial Node. Current Medical Issues 22, 72. https://doi.org/10.4103/cmi.cmi_124_23

3. Mariappan R, Kumar S, Raju K, Daniel D, Nair SC and Subramani S. Comparing two techniques of performing an epidural catheter-assisted epidural blood patch using a 20 ml syringe versus a 5 ml syringe and its effect on clotting time, the strength of clot retraction and haemolysis – A prospective in vitro study (EC-EBP study). Indian J Anaesth. 2023 Jun;67(6):544–7. https://doi.org/10.4103/ija.ija_849_22 

4. Farhan Adam Mukadam, Naveen Gangadharan, Bowya Baskaran, S. Baskaran, Subramani Kandasamy, Syrpailyne Wankhar, Suresh Devasahayam and Sathya Subramani​. Blood pressure variability from intra-arterial pressure recordings in humans. Indian J Physiol Pharmacol 2023; 67(3): 181-190. https://dx.doi.org/10.25259/IJPP_61_2023

5. Kawin Padmaja, Roshni Parameswaran, G Srisangeetha, Shikha Mary Zachariah, Neetu Prince, Soosai Manickam Amirtham, Uwe Beifuss, Juergen Conrad and Sathya Subramani. Cleistanthin A Causes Peripheral Vasoconstriction and Myocardial Depression in Isolated Tissue Preparations. Toxicology Mechanisms and Methods. July 2023. http://dx.doi.org/10.1080/15376516.2023.2237581

6. Intra-arterial blood pressure measurement: sources of error and solutions. Suresh Devasahayam, Naveen Gangadharan, C. Surekha, Bowya Baskaran, Farhan Adam Mukadam and Sathya Subramani. Medical & Biological Engineering & Computing volume 60, pages1123–1138 (2022) https://doi.org/10.1007/s11517-022-02509-z

7. Sajo Thomas​, Soosai A. Manickam, Farhan Adam Mukadam, Aravindan V, and Sathya Subramani. A rat model of septic shock using live Escherichia coli and response to Noradrenaline. Indian Journal of Physiology and Pharmacology. August 2022. https://dx.doi.org/10.25259/IJPP_449_2021

8. Electrical modelling of tissue experiments confirms precise locations of resistance and compliance in systemic arterial tree—they are mutually exclusive. Naveen Gangadharan, Aravindhan Venkatachalapathi, Benjamin Jebaraj, Shikha Mary Zachariah, Suresh Devasahayam, Gurunathan Saravana Kumar and Sathya Subramani. Clinical and Experimental Pharmacology and Physiology October 2021 https://doi.org/10.1111/1440-1681.13606

9. Amirtham SM, Prince N, Venkateswarulu M, Chandra Mondal I, Raman S, Raj R, Rajendran E, Jebaraj B, Vaithiyalingam A, Rajasegaran R, Mukadam FA, Bhaskar A, Ghosh S, Conrad J, Beifuss U and Subramani S. Elusive Toxin in Cleistanthus collinus Causing Vasoconstriction and Myocardial Depression: Detailed NMR Analyses and Biological Studies of Cleistanthoside A. ACS Omega 6: 24553–24561, 2021. https://doi.org/10.1021/acsomega.1c03138

10. Kawin Padmaja Marconi, Bhavithra Bharathi, Alen Major Venis, Renu Raj, Soosai Manickam Amirtham and Sathya Subramani. Phenylephrine induces relaxation of longitudinal strips from small arteries of goat legs. PLoS One. 2020 Mar 3;15(3):e0227316. [Pubmed] [PDF]

11. Kavitha Priya Kettimuthu, Archana Kini, Soosai Manickam Amirtham, A. Amala Louthuraj, Aparna Venkatraman, Sathya Subramani and Anup Ramachandran. Cleistanthus collinus poisoning affects mitochondrial respiration and induces oxidative stress in the rat kidney. Toxicology mechanisms and methods. June 2019; 29(8):1-26. [Pubmed]

12. Renu R. Raj and Sathya Subramani. Phenylephrine decreases vascular tension in goat arteries in specific circumstances. PLOS One. June 30, 2016. [Pubmed] [PDF]

13. Sathya Subramani and Jesi Wilson. The role of sodium-calcium exchanger in rhythm generation in rat heart. Med Ej. Jan-Feb 2015; 5(1) [Link]

14. Sathya Subramani and Neetu Prince. Isolated hind limb preparation to study vascular resistance. Med Ej. Jan-Feb 2015; 5(1) [Link]

15. Sathya Subramani and Pijush Kanti Bagchi. Short term effect of zinc on major blood electrolytes in wistar rat. Med Ej. Jan-Feb 2015; 5(1) [Link]

16. Subramani S, Gnanasenthil G and Kanthakumar P. Effect of partial pressures of end expiratory gases on voluntary breathholding time. Med Ej. Feb 2012; 2(1). [Link]

17. Kettimuthu KP, Lourthuraj AA, Manickam AS, Subramani S and Ramachandran A. Mechanism of Toxicity of Cleistanthus collinus: vacuolar ATPases are a putative target. Clin Toxicol. 2011;49(6):457-63. [Pubmed]

18. Subramani S, Kanthakumar P, Maneksh D, Sidharthan A, Rao SV, Parasuraman V and Tharion E. O2-CO2 diagram as a tool for comprehension of blood gas abnormalities. Adv Physiol Edu. 2011 Sep;35(3):314-20. [Pubmed] [PDF]

19. Tharion E and Subramani S. Ventilatory equivalents for carbondioxide and oxygen are measures of ventilatory efficiency and not of pulmonary gas exchange efficiency. Exp Physiol. 2011 Jul;96(7):709. [Pubmed]

20. Oommen V and Subramani S. Analysis of depolarization-induced outward currents in goat chondrocytes using the patch clamp technique. Indian J. Physiol. Pharmacol.2010 Dec; 54(4):361-365. [Pubmed]

21. Maneksh D, Sidharthan A, Kettimuthu K, Kanthakumar P, Lourthuraj AA, Ramachandran A & Subramani S. Cleistanthus collinus induces type I distal renal tubular acidosis and type II respiratory failure in rats. Indian J Pharmacol. 2010 May;42(3):178-184. [Pubmed] [PDF]

22. Indirani Kanakasabapathy, Silviya Rajakumari J, Sathya Subramani, Prakasa Rao J. Mitochondria-rich Cells in South Indian Green Pond Frog (euphlyctishexadactylus) - A light And Electron Microscopic Study. J Anat Soc India. 2009 Dec;58(2):126-129. [PDF]

23. Jared SR, Rao JP, Subramani S. Actions of Anti Diuretic Hormone analogues on intact and nystatin-permeabilized frog skins. Exp Physiol. 2009 Dec;94(12):1174-84. [Pubmed]

24. Rajpathy J, Aswathaman K, Sinha M, Subramani S, Gopalakrishnan G, Kekre NS. An in vitro study on human ureteric smooth muscle with the alpha1-adrenoceptor subtype blocker, tamsulosin. BJU Int. 2008 Dec;102(11):1743-1745. [Pubmed]

25. Bhaskar A, Subbanna PK, Arasan S, Rajapathy J, Rao JP, Subramani S. 4-aminopyridine-induced contracture in frog ventricle is due to calcium released from intracellular stores. Indian J. Physiol. Pharmacol. 2008 Dec;52(4):366-374. [Pubmed] [PDF]

26. Subramani S, Subbanna PKT. Calcium-transporters in myocardial cells. Indian J. Physiol. Pharmacol. 2006 Jun;50(2):99-113. [Pubmed] [PDF]

27. Subramani S, Balakrishnan S, Jyoti T, Mohammed AA, Arasan S, Vijayanand C. Force-frequency relation in frog-ventricle is dependent on the direction of sodium/calcium exchange in diastole. Acta Physiol. Scand. 2005 Nov;185(3):193-202. [Pubmed]

28. Subramani S, Vijayanand C, Tharion E. Differential effects of organic calcium-channel blockers on diastolic SR calcium-handling in the frog heart. Br. J. Pharmacol. 2002 Nov;137(6):756-760. [Pubmed]

29. Subramani S, Mammen P. Extra systoles in the frog heart. Indian J. Physiol. Pharmacol. 2001 Oct;45(4):511-513. [Pubmed] [PDF]

30. Sathya K, Balamurugan AN, Savithiri S, Gunasekaran S. Intravenous glucose tolerance test in Macaca radiata radiata. Indian J. Physiol. Pharmacol. 1997 Apr;41(2):176-178. [Pubmed]

Conference presentations

1. Kettimuthu K, Ramachandran A, Lourthuraj AA, Manickam SA and Subramani S. (2009) Mechanism of Toxicity of Cleistanthus Collinus: Vacuolar H+ ATPases Are a Putative Target. Clin Toxicol. 47(7):724. [Link][PDF]

2. Bhaskar A, Subbanna PK, Rao JP and Subramani S.(2007) 4-Aminopyridine-sensitive Ca2+ store in frog ventricle. Proc Physiol Soc. PC2. [Link] [PDF]

3. Subramani S, Jyoti T, Sathishkumar S, Balakrishnan S, Mohammed A and Vijayanand C. Force-frequency relation in frog-ventricle (2003). J Physiol. 552P:C38. [Link]

4. Subramani S, Tharion E and Vijayanand E. Novel actions of some organic calcium channel blockers on frog myocardium (2002). J Physiol. 543P:S236. [Link]

5. Subramani S, Chow RH, Shipston MJ, Kerrigan MJ and Hall AC (2001). Histamine induced exocytosis in bovine articular chondrocytes. J Physiol 531P: 128P.