The role of the sodium pump in the developmental regulation of membrane electrical properties of cerebellar Purkinje neurons of the rat.
The postnatal development of the rat cerebellum has been well described morphologically and functionally. However, information regarding the electrical characteristics of Purkinje neurons during development is sparse. Using standard intracellular recording, the basic electrical properties of Purkinje neurons in cerebellar slices were compared at different postnatal ages. There was a significant, progressive increase in the resting membrane potential (RMP) of Purkinje neurons with age as well as a small but significant decrease in the cellular input resistance (Rin). The cardiac glycoside, ouabain (1 mM), an inhibitor of the sodium pump, depolarized Purkinje neurons significantly more with age. The magnitude of the increase in depolarizing activity of ouabain was equivalent to the magnitude of the increase in membrane potential. The number of ouabain binding sites was also found to increase with age suggesting an age related increase in the number of sodium pump sites. These results suggest that the predominant cellular mechanism which underlies the increase in membrane potential of Purkinje neurons during development is an increase in the density of Na+, K+ pump sites and in the contribution of the electrogenic sodium pump.
Molnar
L R
LR
Department of Pharmacology and Toxicology, R.C. Byrd Health Sciences Center, West Virginia University School of Medicine, P.O. Box 9223, Morgantown, WV 26506-9223, USA.
Thayne
K A
KA
Fleming
W W
WW
Taylor
D A
DA
D000375:Aging / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn / Q000254:growth & development / Q000502:physiology*; D001665:Binding Sites / Q000502:physiology; D004594:Electrophysiology; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D010042:Ouabain / Q000378:metabolism / Q000494:pharmacology; D011689:Purkinje Cells / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000502:physiology*
D010042:Ouabain; D000254:Sodium-Potassium-Exchanging ATPase