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Effects of thyroid hormone on the action potential and membrane currents of guinea pig ventricular myocytes
- Source :
- Pflügers Archiv - European Journal of Physiology. 409:214-216
- Publication Year :
- 1987
- Publisher :
- Springer Science and Business Media LLC, 1987.
-
Abstract
- We studied the effects of thyroid hormone on the action potential and membrane currents recorded from enzymatically dissociated guinea pig ventricular myocytes, by means of the whole-cell recording technique. Hypothyroidism was associated with an increase in action potential duration, whereas hyperthyroidism was associated with a decrease in duration. These effects are similar to those reported in multicellular preparations. Hypo- and hyperthyroidism were also associated with a decrease and an increase, respectively, in the slope of the action potential plateau. Resting potential and action potential amplitude were unaffected by the alterations in the thyroid state. The voltage-clamp experiments revealed that as compared with euthyroid myocytes, the peak calcium current was bigger in hyperthyroid myocytes and smaller in hypothyroid myocytes. The potassium outward current (at a membrane potential = 50 mV) was of similar amplitude in hypo- and euthyroid myocytes and bigger in hyperthyroid myocytes. Our major conclusion is that thyroid hormones regulate the amplitude of the calcium current and that this effect may be responsible in part for the modulation of myocardial contractility by thyroid hormones.
- Subjects :
- endocrine system
medicine.medical_specialty
endocrine system diseases
Physiology
Guinea Pigs
Clinical Biochemistry
Action Potentials
In Vitro Techniques
Biology
Hyperthyroidism
Membrane Potentials
Contractility
Hypothyroidism
Physiology (medical)
Internal medicine
medicine
Animals
Myocyte
Euthyroid
Membrane potential
Thyroid
Heart
Resting potential
Thyroxine
Electrophysiology
medicine.anatomical_structure
Endocrinology
hormones, hormone substitutes, and hormone antagonists
Hormone
Subjects
Details
- ISSN :
- 14322013 and 00316768
- Volume :
- 409
- Database :
- OpenAIRE
- Journal :
- Pflügers Archiv - European Journal of Physiology
- Accession number :
- edsair.doi.dedup.....e71e883b7ebc3f01df691ecd60242cfd