The role of identified neurotransmitter systems in the response of insular cortex to unfamiliar taste: activation of ERK1-2 and formation of a memory trace.
In the behaving rat, the consumption of an unfamiliar taste activates the extracellular signal-regulated kinase 1-2 (ERK1-2) in the insular cortex, which contains the taste cortex. In contrast, consumption of a familiar taste has no effect. Furthermore, activation of ERK1-2, culminating in modulation of gene expression, is obligatory for the encoding of long-term, but not short-term, memory of the new taste (Berman et al., 1998). Which neurotransmitter and neuromodulatory systems are involved in the activation of ERK1-2 by the unfamiliar taste and in the long-term encoding of the new taste information? Here we show, by the use of local microinjections of pharmacological agents to the insular cortex in the behaving rat, that multiple neurotransmitters and neuromodulators are required for encoding of taste memory in cortex. However, these systems vary in the specificity of their role in memory acquisition and in their contribution to the activation of ERK1-2. NMDA receptors, metabotropic glutamate receptors, muscarinic, and beta-adrenergic and dopaminergic receptors, all contribute to the acquisition of the new taste memory but not to its retrieval. Among these, only NMDA and muscarinic receptors specifically mediate taste-dependent activation of ERK1-2, whereas the beta-adrenergic function is independent of ERK1-2, and dopaminergic receptors regulate also the basal level of ERK1-2 activation. The data are discussed in the context of postulated novelty detection circuits in the central taste system.
Berman
D E
DE
Department of Neurobiology, The Weizmann Institute of Science, Rehovot 76100, Israel.
Hazvi
S
S
Neduva
V
V
Dudai
Y
Y
D000319:Adrenergic beta-Antagonists / Q000008:administration & dosage; D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D018680:Cholinergic Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000008:administration & dosage; D018691:Excitatory Amino Acid Antagonists / Q000008:administration & dosage; D008297:Male; D008568:Memory / Q000187:drug effects / Q000502:physiology*; D008845:Microinjections; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018727:Muscarinic Antagonists / Q000008:administration & dosage; D018377:Neurotransmitter Agents / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors / Q000378:metabolism; D011954:Receptors, Dopamine / Q000378:metabolism; D018079:Receptors, GABA / Q000187:drug effects / Q000378:metabolism; D018094:Receptors, Metabotropic Glutamate / Q000037:antagonists & inhibitors / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors / Q000378:metabolism; D012054:Reinforcement, Psychology; D013649:Taste / Q000502:physiology*
D000319:Adrenergic beta-Antagonists; D018680:Cholinergic Antagonists; D018492:Dopamine Antagonists; D018691:Excitatory Amino Acid Antagonists; D018727:Muscarinic Antagonists; D018377:Neurotransmitter Agents; D018091:Receptors, AMPA; D011954:Receptors, Dopamine; D018079:Receptors, GABA; D018094:Receptors, Metabotropic Glutamate; D011976:Receptors, Muscarinic; D016194:Receptors, N-Methyl-D-Aspartate; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases