Abstract
Olfactory receptor neurons respond to odor stimulation with an inward cationic current. Under whole-cell patch clamp, individual, isolated olfactory receptors were exposed to pharmacological agents known to interact with distinct enzymes in a putative second messenger cascade, and their response to odors was measured. IBMX prolonged the odor-evoked current and also reduced its amplitude. cAMP and cGMP induced a current electrically identical to the odor current, but the current showed desensitization only with cAMP. GTP-gamma-s prolonged and GDP-beta-s interfered with the odor-evoked current. The long latency seen in the odor response appears to be mainly due to the loading of the G protein and secondarily to the requirement for cAMP accumulation. The main source of the response decay appears to be cyclic nucleotide hydrolysis.
Publication types
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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1-Methyl-3-isobutylxanthine / pharmacology
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Animals
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Cyclic AMP / pharmacology
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Cyclic AMP / physiology*
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Cyclic GMP / analogs & derivatives
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Cyclic GMP / pharmacology
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Cyclic GMP / physiology
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Electrophysiology
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GTP-Binding Proteins / physiology*
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Guanosine 5'-O-(3-Thiotriphosphate) / analogs & derivatives
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Guanosine 5'-O-(3-Thiotriphosphate) / pharmacology
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Hydrolysis
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Neurons / physiology
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Odorants
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Phosphoric Diester Hydrolases / physiology
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Protein Kinases / physiology*
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Second Messenger Systems / drug effects
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Second Messenger Systems / physiology*
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Sensory Receptor Cells / physiology*
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Smell / physiology*
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Urodela / physiology*
Substances
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guanosine 5'-O-(1-thiotriphosphate)
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guanosine 5'-O-(2-thiotriphosphate)
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8-bromocyclic GMP
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Guanosine 5'-O-(3-Thiotriphosphate)
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Cyclic AMP
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Protein Kinases
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Phosphoric Diester Hydrolases
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GTP-Binding Proteins
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Cyclic GMP
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1-Methyl-3-isobutylxanthine