Inhibition of human alpha4beta2 neuronal nicotinic acetylcholine receptors by volatile aromatic anesthetics depends on drug hydrophobicity
Language: 
English
Abstract: 

BACKGROUND: Volatile aromatic compounds such as benzene are general anesthetics that cause amnesia, hypnosis, and immobility in response to noxious stimuli when inhaled. Although these compounds are not used clinically, they are frequently found in commercial items such as solvents and household cleaning products and are abused as inhalant drugs. Volatile aromatic anesthetics are useful pharmacological tools for probing the relationship between chemical structure and drug activity at putative general anesthetic targets. Neuronal nicotinic acetylcholine (nACh) receptors are ligand-gated ion channels widely expressed in the brain, which are thought to play important roles in learning and memory. In this study, we tested the hypothesis that aromatic anesthetics reversibly inhibit alpha(4)beta(2) neuronal nACh receptor function and sought to determine the structural correlates of receptor inhibition. METHODS: Electrophysiological techniques were used to quantify the effects of 8 volatile aromatic anesthetics on currents elicited by 1 mM ACh and mediated by human alpha(4)beta(2) nACh receptors expressed in Xenopus oocytes. RESULTS: All of the volatile aromatic anesthetics used in this study reversibly inhibited alpha(4)beta(2) nACh receptors with IC(50) values ranging from 0.00091 atm for 1,2-difluorobenzene to 0.045 atm for hexafluorobenzene. With the exception of hexafluorobenzene, all of the compounds had IC(50) values less than minimum alveolar concentration. Inhibitory potency correlated poorly with the cation-pi binding energies of the compounds (r(2) = 0.48, P = 0.059). However, there was a good correlation between inhibitory potency and the octanol/gas partition coefficient (r(2) = 0.87, P = 0.0008). CONCLUSIONS: Volatile aromatic anesthetics potently and reversibly inhibit human alpha(4)beta(2) neuronal nACh receptors. This inhibition may play a role in producing amnesia. In contrast to N-methyl-d-aspartate receptors, the inhibitory potencies of aromatic anesthetics for alpha(4)beta(2) neuronal nACh receptors seem to be dependent on drug hydrophobicity rather than electrostatic properties. This implies that the volatile aromatic anesthetic binding site in the alpha(4)beta(2) neuronal nACh receptor is hydrophobic in character and differs from the nature of the binding site in N-methyl-D-aspartate receptors.

Author(s): 
Solt, Ken
Kelly, Elizabeth W.
Cotten, Joseph F.
Raines, Douglas E.
Item Type: 
Journal Article
Publication Title: 
Anesthesia and Analgesia
Journal Abbreviation: 
Anesth. Analg.
Publication Date: 
2/1/2010
Publication Year: 
2010
Pages: 
455-460
Volume: 
110
Issue: 
2
ISSN: 
1526-7598
DOI: 
10.1213/ANE.0b013e3181c5f689
Library Catalog: 
PubMed
Extra: 
PMID: 19917625 PMCID: PMC3534757

Turabian/Chicago Citation

Ken Solt, Elizabeth W. Kelly, Joseph F. Cotten and Douglas E. Raines. 2/1/2010. "Inhibition of human alpha4beta2 neuronal nicotinic acetylcholine receptors by volatile aromatic anesthetics depends on drug hydrophobicity." Anesthesia and Analgesia 110: 2: 455-460. 10.1213/ANE.0b013e3181c5f689.

Wikipedia Citation

<ref> {{Cite journal | doi = 10.1213/ANE.0b013e3181c5f689 | issn = 1526-7598 | volume = 110 | pages = 455-460 | last = Solt | first = Ken | coauthors = Kelly, Elizabeth W., Cotten, Joseph F., Raines, Douglas E. | title = Inhibition of human alpha4beta2 neuronal nicotinic acetylcholine receptors by volatile aromatic anesthetics depends on drug hydrophobicity | journal = Anesthesia and Analgesia | date = 2/1/2010 | pmid = | pmc = }} </ref>