Cyclic nucleotide–gated channels, calmodulin, adenylyl cyclase, and calcium/calmodulin-dependent protein kinase II are required for late, but not early, long-term memory formation in the honeybee

Abstract

Memory is a dynamic process that allows encoding, storage, and retrieval of information acquired through individual experience. In the honeybee Apis mellifera, olfactory conditioning of the proboscis extension response (PER) has shown that besides short-term memory (STM) and mid-term memory (MTM), two phases of long-term memory (LTM) are formed upon multiple-trial conditioning: an early phase (e-LTM) which depends on translation from already available mRNA, and a late phase (l-LTM) which requires de novo transcription and translation. Here we combined olfactory PER conditioning and neuropharmacological inhibition and studied the involvement of the NO-cGMP pathway, and of specific molecules, such as cyclic nucleotide-gated channels (CNG), calmodulin (CaM), adenylyl cyclase (AC), and Ca 2+ /calmodulin-dependent protein kinase (CaMKII), in the formation of olfactory LTM in bees. We show that in addition to NO-cGMP and cAMP-PKA, CNG channels, CaM, AC, and CaMKII also participate in the formation of a l-LTM (72-h post-conditioning) that is specific for the learned odor. Importantly, the same molecules are dispensable for olfactory learning and for the formation of both MTM (in the minute and hour range) and e-LTM (24-h post-conditioning), thus suggesting that the signaling pathways leading to l-LTM or e-LTM involve different molecular actors.

Searching for cognitive processes underlying insect learning

“…We showed that the MER to an odor is increased by pairing of the odor with water US. This is analogous to olfactory conditioning of proboscis extension responses (PERs) in honey bees, in which pairing of an odor and sucrose US leads to an increase of the PER (Menzel & Giurfa, 2006;Matsumoto, Sandoz, Devaud, Lormant, Mizunami, & Giurfa, 2014). We also showed that the MER to an odor is decreased by pairing of the odor with sodium chloride US, thus allowing study of appetitive conditioning and aversive conditioning in a similar experimental situation.…”

Weight of evidence evaluation of a network of adverse outcome pathways linking activation of the nicotinic acetylcholine receptor in honey bees to colony death

“…In the honey bee, seven ACs have been identified, with transmembrane AmAC8 likely belonging to the Ca 2+ -CaM activated enzyme family (Balfanz et al, 2012). Matsumoto et al (2014) injected pharmacological inhibitors of AC directly into the brain of honey bees and observed impairment of long-term memory. Such studies with inhibitors provide evidence of the essentiality of proper AC signaling.…”

CaMKII knockdown affects both early and late phases of olfactory long-term memory in the honeybee

“…Whereas earlier attempts to unravel molecular and biochemical pathways associated with learning and memory in the honeybee were often based on pharmacological tools (e.g. Felsenberg et al, 2011;Müller, 1996Müller, , 2000, in recent years manipulations using genetic tools such as RNA interference (RNAi) became more accessible (El Hassani et al, 2012;Farooqui et al, 2003;Louis et al, 2012;Matsumoto et al, 2014;Müssig et al, 2010). The possibilities for a combination of several manipulative approaches and the availability of robust associative learning assays make the honeybee an excellent model organism to study the link between behavioral plasticity and its molecular basis.…”