Again about central metabotropic glutamate receptors of the group I in the honeybee Apis mellifera

Abstract

head ganglion after the injections was evaluated by using an immunohistochemical method.The object of the study served honeybees of the krain race Apis mellifera carnica Polm at the age of 10-15 days. According to the posed tasks of the work, we used the behavioral and immunocytochemical methods of the study.Behavioral test. The elaboration of conditioned reflexes (CR) started from that 3 h before the beginning of experiment the honeybees were deprived of food to achieve the standard level of the conditioned-unconditioned reflex backgrounds. Prior to the learning performance the sensory and alimentary excitabilities were evaluated. The conditioned reflex of the proboscis pulling was elaborated in the honeybees immobilized by wings at the single combination of the conditioned stimulus (carnation smell) with the unconditioned alimentary reinforcement (the 50% sucrose solution).Immunohistochemical method. The insects were submitted to the cold narcosis and the brain was removed and fixed in paraformaldehyde for 4 h. The tissue was dehydrated in ethanols (40, 70, 96, and 100%) and in a methylbenzoate:paraffin, then immersed into a mixture methylbenzoate-paraf-The study of metabotropic L-glutamate receptors (mGluR) was begun in the mid-1980s [1]. The first publications about the presence of mGluR in the invertebrate head ganglion and their role in learning appeared at the mid-1990s [2]. Our studies allowed us to conclude [3] about the presence in the honeybee head ganglion of I, II и III groups of mGluR responsible for the long-term preservation of the individually acquired experience, with the receptors similar by the pharmacological profile to those in mammals. Our data differed from those obtained in studies of the foreign authors showing the presence in the honeybee head ganglion only of mGluR of the II group [4,5]. It was necessary to obtain additional proofs in favor of the function/absence in the honeybee head ganglion of the heterogeneous mGluR group (I, II, III). Considering the presence of homology between the sequences of the I and II groups of mGluR, we needed the method that would allow identification particularly of the mGluR taking part in the honeybee associative learning. As such method, we used the knock-down method of ImGluR1 with aid of antisense oligonucleotide (asON). The goal of this work was the study of the behavioral consequences of intracerebral asON injections. The ImGluR1 state in the honeybee

Metabotropic receptor of the group I of the 5th subtype (ImGluR5) in honeybee associative olfactory learning

“…The pattern of the ImGluR5 expression differs from that for ImGluR1: ImGluR5 is expressed in Kenyon cells (neuronal bodies), ImGluR1-in calyx (neuropil) of the mushroom bodies [17]. In the studies on mammals it is emphasized the some complementariness in the distribution of ImGluR1 and Im-GluR5 in the structures of brain, but at the same time a moving character of their localization.…”

“…The receptors of this subtype were identified and localized, their significance was shown in formation of the long-term memory. There was shown the predominant expression of the receptor in neuropil of mushroom bodies [16,17]. The inhibition of the process of formation of the long-term memory by the selective antagonist I mGluR5 SIB 1757 [16] allowed suggesting participation of this subtype of receptor in the associative learning of honeybees.…”