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Pflügers Archiv

, Volume 419, Issue 6, pp 579–582 | Cite as

β subunits determine the time course of desensitization in rat α3 neuronal nicotinic acetylcholine receptors

  • Armand B. Cachelin
  • Rolf Jaggi
Excitable Tissues and Central Nervous Physiology

Abstract

Standard two-electrode voltage-clamp techniques were used to investigate some of the pharmacological and functional properties of two types of rat neuronal nicotinic acetylcholine receptors expressed in Xenopus oocytes after pairwise injection of α3β4 or α3β2 mRNAs. Currents of several μA amplitude were elicited by fast application of micromolar concentrations of either acetylcholine (ACh) or 1,1-dimethyl-4-piperazine (DMPP). The activation of either receptor type by DMPP showed cooperativity (Hill coefficient, n≥1.7) with a half-maximal activation concentration (EC50) of 15–30 μM. In α3β4 receptors, ACh displayed cooperativity (n=1.8) but was less efficacious than DMPP, yet its EC50 was about equal to that of DMPP. Finally, in α3β2 receptors, ACh was much less efficacious and had a much lower EC50. Desensitization induced by either DMPP or ACh was slow in α3β4 nicotinic ACh receptors but was rapid and extensive in α3β2 receptors, causing a significant proportion of the response to wane within the first few seconds of agonist application.

Key words

Neuronal nicotinic acetylcholine receptor Xenopus oocytes Voltage clamp Desensitization β subunits 

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Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • Armand B. Cachelin
    • 1
  • Rolf Jaggi
    • 2
  1. 1.Department of PharmacologyUniversity of BerneBerneSwitzerland
  2. 2.Department of Clinical and Experimental ResearchUniversity of BerneBerneSwitzerland

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