Reversible downregulation of protein kinase A during olfactory learning using antisense technique impairs long-term memory formation in the honeybee, Apis mellifera.
In this study, we examined the role of cAMP-dependent protein kinase (PKA) in associative olfactory learning of the honeybee, Apis mellifera. In the bee, specific interference with molecules to clarify their role in a certain behavior is difficult, because genetic approaches, such as mutants or transgenic animals, are not feasible at the moment. As a new approach in insects in vivo, we report the use of short antisense oligonucleotides. We show that phosphorothioate-modified oligodeoxynucleotides complementary to the mRNA of a catalytic subunit of PKA directly injected into the bee brain cause a reversible and specific downregulation of both the amount of the catalytic subunit and of PKA activity by 10-15%. The amounts of the regulatory subunit of PKA, as well as PKC, are not affected. The slight "knockdown" of PKA activity during the training procedure, a classical olfactory conditioning of the proboscis extension reflex, neither affects acquisition nor memory retention 3 or 6 hr after training. However, it causes an impairment of long-term memory retention 24 hr after training. Downregulation of PKA 3 hr after training has no detectable effect on memory formation. We conclude that PKA contributes to the induction of a long-term memory 24 hr after training when activated during learning. Second, we demonstrate that the antisense technique is feasible in honeybees in vivo and provides a new and powerful tool for the study of the molecular basis of learning and memory formation in insects.
Fiala
A
A
Institut für Neurobiologie der Freien Universität Berlin, 14195 Berlin, Germany. fiala@zedat.fu-berlin.de
Müller
U
U
Menzel
R
R
D000818:Animals; D001516:Bees / Q000502:physiology*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000032:analysis / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D007858:Learning / Q000502:physiology*; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D009812:Odorants; D009833:Olfactory Pathways / Q000502:physiology; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D013873:Thionucleotides; D014158:Transcription, Genetic
D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; D013873:Thionucleotides; D017868:Cyclic AMP-Dependent Protein Kinases