Additionally, activation of glutamate
metabotropic receptors and neurotrophin receptors, such as Trk, also induces activation of PKC [right arrow] MEK [right arrow] MAPK pathways [83, 84].
It functions by binding to receptors on nerve and effector cells that gate ions direcT1y, through channel pores in the receptor (ionotropic glutamate receptors, iGluRs; see Dingledine et al., 1999, for a review), or indirecT1y, through a series of intracellular metabolic steps (
metabotropic receptors, mGluRs; see Pin and Duvoisin, 1995, for a review).
[35] provided very powerful evidence in vitro, ex vivo (acute slice preparation), and in vivo for the regulation of ATP-induced microglial chemotaxis by the P2Y12
metabotropic receptor as branch extension or migration-towards purinergic sources was abolished or significantly delayed in P2Y12 knockout microglia.
Glutamate modulates ionotropic N-methyl-D-aspartate (NMDA) and [alpha]-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, and a family of nonionic
metabotropic receptors, or mGluRs.
[GABA.sub.B] receptors are G protein-coupled
metabotropic receptors which are widely distributed in the central nervous system, especially in the spinal cord dorsal horn [45].
Twenty chapters are divided into four parts: neurons: excitable and secretory cells that establish synapses; ionotropic and
metabotropic receptors in synaptic transmission; somato-dendritic processing and plasticity of postsynaptic potentials; the hippocampal network.
This molecule is able to activate a family of
metabotropic receptors ([mu]-, [delta]-, and [kappa]-type opioid receptors).
Two classes of glutamate receptors exist: ionotropic receptors (iGluRs), and
metabotropic receptors (mGluRs).
Ionotropic and
metabotropic receptors, protein kinase A, protein kinase C, and Src contribute to C-fiber-induced ERK activation and cAMP response element-binding protein phosphorylation in dorsal horn neurons, leading to central sensitization.
Other receptors, N-methyl-D-aspartate (NMDA) receptor, also belong to the ion-channel-linked superfamily, and there is a population of
metabotropic receptors, as upon activation they simulate a second messenger transduction system [7].
The hypothesis that
metabotropic receptors make a greater contribution to the process of learning is compatible with the idea of the more essential role of this type of receptor, compared to ionotropic ones, in the dynamics of nerve component plasticity (Eccles & McGreer, 1979).
Metabotropic receptors generally produce slower and longer-lasting reactions at the synapse that have modulatory effects rather than generate new nerve signals.
