Calcium–hydrogen exchange by the plasma membrane Ca-ATPase of voltage-clamped snail neurons

Glutamate (GLU) mediates its 'fast' excitatory transmitter action in the brain by directly gating cation-selective ion channels ('ionotropic' receptors). However, GLU can also activate another type of receptor, coupled to phospholipase C ('metabotropic' receptor). In hippocampal cells, stimulation of this metabotropic receptor by GLU, or by a racemic mixture of (1S-3R and 1R-3S) 1-aminocyclopentyl-1,3-dicarboxylate (ACPD), induces a slower excitation mediated by inhibition of K+ currents. We have assessed whether this slow form of metabotropic receptor excitation can contribute to the effects of synaptically released GLU in hippocampal slice cultures, by recording the responses of CA3 pyramidal cells to afferent mossy fibre stimulation. When the fast ionotropic response was blocked pharmacologically, mossy fibre stimulation produced a slow depolarizing postsynaptic potential associated with a decrease in membrane conductance, a depression of the slow after-hyperpolarization following a train of action potentials, and reduced accommodation during the action potential train. Under voltage-clamp, mossy fibre stimulation produced a slow voltage-dependent inward current which resembled that produced by application of exogenous ACPD or quisqualate (QUIS), and which was occluded by these metabotropic agonists. We therefore suggest that synaptically released GLU can induce two types of postsynaptic responses: a fast excitation through activation of ionotropic receptors and a slower excitation associated with inhibition of K+ conductances through activation of metabotropic receptors. This is analogous to the dual action of acetylcholine on ionotropic (nicotinic) and metabotropic (muscarinic) receptors.

Structure and function of the brain serotonin system

Electrotonic coupling between neurons in cat inferior olive.

Intracellular pH.

This review concentrates on the results of quantal analysis at central synapses, particularly where the morphology and the electrophysiology of the same synaptic connection has been investigated. Results from quantal analysis at peripheral synapses are drawn on to help resolve some issues. The major topics covered in this review are the properties of the quantal synaptic potential and the junctional mechanisms involved in its generation

Electrophysiology of hippocampal neurons. I. Sequential invasion and synaptic organization.

Spreading cortical depression of Leao.

Visual and oculomotor functions of monkey substantia nigra pars reticulata. III. Memory-contingent visual and saccade responses.

Optical imaging of neuronal activity.

Ce rapport analyse l'organisation anatomique du systeme limbique, ses principales connexions avec les autres compartiments du cerveau et sa physiologie en rapport avec le comportement de l'animal

1. Monkeys were trained to look to brief visual targets presented in a completely darkened room. On some trials, after the visual target disappeared but before a saccade to the target could be initiated, the eyes were driven to another position in the orbit by electrical stimulation of the superior colliculus. Retinocentric models of the saccadic system predict that a saccade with a predetermined distance and direction based entirely on retinal error will occur. If this were the case, gaze would miss the target location by a distance and direction equal to the vector of the stimulation-induced movement. Spatial models assume that the retinal error signal will be combined with information about the change in eye position produced by stimulation and predict that the animal will look to the position of the target in space. 2. Results confirm the predictions of spatial models. Animals compensated for the stimulation-induced perturbation by looking to the position of the target in space. The result predicted by retinocentric models-a saccade with a direction and amplitude based on retinal error alone-was never observed. 3. The eye movement that compensated for the change in eye position produced by stimulation was a saccade, not a passive, lowvelocity movement to an orbital position of mechanical equilibrium established by a tonic pattern of motoneuron activation specified by the visual target. This indicates that a new saccade command, based on stored information about the location of the retinal image and information about the new position of the eyes, had been issued. Computation of the vector of the compensatory saccade does not necessarily increase the latency of target acquisition. The interval between the end of a stimulation-induced saccade and the beginning of the compensatory saccade was frequently 20 ms or less, permitting the animal to acquire the target with a normal latency.

Afterpotential generation in hippocampal pyramidal cells.

Response of binaural neurons of dog superior olivary complex to dichotic tonal stimuli: some physiological mechanisms of sound localization.

Biochemistry and physiology of brain ammonia.

Major topics addressed in this review on neurotransmitters and neuromodulators of the mammalian cochlea are ; 2) neuronal circuity of the organ of Corti ; 2) hair cell neurotransmitter(s) ; efferent neurotransmitters and neuromodulators (acetylcholine, γ-aminobutyric acid, dopamine, enkephalins, dynorphins, calcitonin gene-related peptide, excitatory amino acids ; and 3) other neuroactive substances in the cochlea (adenosine, ATP, taurine, auditory nerve-activating substance, histamine)