Nitric oxide/cGMP-mediated protein kinase A activation in the antennal lobes plays an important role in appetitive reflex habituation in the honeybee.
Habituation, a form of non-associative learning, is observed throughout the animal kingdom. However, in contrast to associative learning, little is known about the underlying molecular mechanisms. Using the appetitive proboscis extension reflex in honeybees, we show that the cAMP-dependent protein kinase A (PKA) in the antennal lobe (AL) is implicated in the graded decline of behavioral response during habituation. Repeated stimulation leads to a slow and gradual increase in PKA activity superimposed on a fast transient PKA activation induced by each stimulus. These temporally distinct components of PKA activation are pharmacologically dissectible and are restricted to the AL on the stimulated side. Whereas the transient PKA activation induced by each stimulus requires monoaminergic transmission, the slow component of PKA activation is mediated by the nitric oxide (NO)/cGMP system. Local manipulation of the slow component of PKA activation in single ALs specifically interferes with the dynamic of habituation on the corresponding side. Our results provide strong evidence that NO/cGMP-mediated PKA activation in each AL contributes to temporal signal integration during habituation. Dishabituation by a sensory stimulus or spontaneous recovery from habituation does not require the PKA cascade. This provides evidence that the mechanisms underlying dishabituation and spontaneous recovery differ from those underlying temporal signal integration during habituation of the proboscis extension response.
D000818:Animals; D001070:Appetitive Behavior / Q000187:drug effects / Q000502:physiology*; D001516:Bees / Q000502:physiology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D002628:Chemoreceptor Cells / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006152:Cyclic GMP / Q000378:metabolism*; D017869:Cyclic GMP-Dependent Protein Kinases / Q000037:antagonists & inhibitors; D004333:Drug Administration Routes; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017952:Ganglia, Invertebrate / Q000502:physiology; D006185:Habituation, Psychophysiologic / Q000187:drug effects / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors; D020127:Recovery of Function / Q000502:physiology; D012018:Reflex / Q000187:drug effects / Q000502:physiology; D015290:Second Messenger Systems / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology; D013268:Stimulation, Chemical; D013395:Sucrose / Q000008:administration & dosage
D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D013395:Sucrose; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D017869:Cyclic GMP-Dependent Protein Kinases; D011493:Protein Kinase C; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D006152:Cyclic GMP