Involvement of alpha-bungarotoxin-sensitive nicotinic receptors in long-term memory formation in the honeybee (Apis mellifera).
In the honeybee Apis mellifera, multiple-trial olfactory conditioning of the proboscis extension response specifically leads to long-term memory (LTM) which can be retrieved more than 24 h after learning. We studied the involvement of nicotinic acetylcholine receptors in the establishment of LTM by injecting the nicotinic antagonists mecamylamine (1 mM), alpha-bungarotoxin (alpha-BGT, 0.1 mM) or methyllycaconitine (MLA, 0.1 mM) into the brain through the median ocellus 20 min before or 20 min after multiple-trial learning. The retention tests were performed 1, 3, and 24 h after learning. Pre-training injections of mecamylamine induced a lower performance during conditioning but had no effect on LTM formation. Post-training injections of mecamylamine did not affect honeybees' performances. Pre-training injections of MLA or post-training injection of alpha-BGT specifically induced LTM impairment whereas acquisition as well as memory retrieval tested 1 or 3 h after learning was normal. This indicates that brain injections of alpha-BGT and MLA did not interfere with learning or medium-term memory. Rather, these blockers affect the LTM. To explain these results, we advance the hypothesis that honeybee alpha-BGT-sensitive acetylcholine receptors are also sensitive to MLA. These receptors could be essential for triggering intracellular mechanisms involved in LTM. By contrast, medium-term memory is not dependent upon these receptors but is affected by mecamylamine.
Gauthier
Monique
M
Centre de Recherches sur la Cognition Animale, CNRS/Université Paul Sabatier Toulouse III, 4R3, 118 route de Narbonne, 31062 Toulouse Cedex 09, France. gauthiem@cict.fr
Dacher
Matthieu
M
Thany
Steeve Hervé
SH
Niggebrügge
Claudia
C
Déglise
Patrice
P
Kljucevic
Pierre
P
Armengaud
Catherine
C
Grünewald
Bernd
B
D000157:Aconitine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001245:Association Learning / Q000187:drug effects / Q000502:physiology*; D001516:Bees; D002038:Bungarotoxins / Q000494:pharmacology*; D018678:Cholinergic Agents / Q000494:pharmacology; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D008464:Mecamylamine / Q000494:pharmacology; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D011978:Receptors, Nicotinic / Q000145:classification* / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D012903:Smell / Q000502:physiology
D002038:Bungarotoxins; D018678:Cholinergic Agents; D011978:Receptors, Nicotinic; C054634:methyllycaconitine; D008464:Mecamylamine; D000157:Aconitine