This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a colleague Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (3) Citing Articles via Google Scholar Google Scholar Articles by Hirota, K. Articles by Ito, Y. Search for Related Content PubMed PubMed Citation Articles by Hirota, K. Articles by Ito, Y.

---

GENERAL ARTICLES

Volatile Anesthetics Reduce Calcium Current in Parasympathetic Neurons from Bullfrog Hearts

Department of Anesthesiology, Toyama Medical and Pharmaceutical University School of Medicine, Toyama, Japan

Address correspondence and reprint requests to Dr. Hirota, Department of Anesthesiology, Toyama Medical and Pharmaceutical University School of Medicine, 2630 Sugitani, Toyama 930-0194, Japan.

Although the autonomic nervous system regulates cardiac function, the cellular mechanism(s) of general anesthetics on the activities of parasympathetic neurons have not been directly assessed. We therefore studied the volatile anesthetic actions on the Ca²⁺ current of parasympathetic neurons isolated from bullfrog hearts. Neurons were enzymatically isolated from the interatrial septum of bullfrog heart and maintained in a short-term tissue culture. The Ca²⁺ current was recorded with a whole-cell voltage-clamp method under a Na⁺, K⁺-free condition. Isoflurane (2.5 vol%) and sevoflurane (5.0 vol%) reduced the peak amplitude of the Ca²⁺ current (to 79% and 72% of control, respectively) without changing the reversal potential. The curve-fit analysis of the inactivation kinetics revealed that isoflurane and sevoflurane accelerated the inactivation of the current and that isoflurane shifted the midpoint of the steady-state inactivation curve of the Ca²⁺ current toward negative by 13.6 mV. The results indicate that volatile anesthetics reduce the Ca²⁺ current of parasympathetic neurons and modify the inactivation kinetics.

Implications: The anesthetic reduction of the Ca²⁺ current of parasympathetic neurons can induce a decrease of acetylcholine release from the postganglionic endings. These findings, in part, account for the anesthetic attenuation of the vagal efferent activities observed in humans and experimental animals.

This article has been cited by other articles:

				A. Kitamura, W. Marszalec, J. Z. Yeh, and T. Narahashi Effects of Halothane and Propofol on Excitatory and Inhibitory Synaptic Transmission in Rat Cortical Neurons J. Pharmacol. Exp. Ther., January 1, 2003; 304(1): 162 - 171. [Abstract] [Full Text] [PDF]