Hippocampus glutamatergic neurons

The hippocampus is characterized by a series of glutamatergic neurons, which can create rhythms of electrical activity necessary for the generation of memory traces in the brain. The cerebellum, a region dedicated to the temporal processing of motor and cognitive in-... 

Several brain functions have been linked to specific glutamate receptor subtypes in selected brain regions. For example, glutamatergic neurons and NMDA receptors in the hippocampus are important for longterm potentiation (FTP), a crucial component in the formation of memory (Wilson and Tonegawa, 1997). Animal models with selective lesioning or strengthen-... 

Figure 30-13 Section through a rat brain. This brain, which has been very widely used in neurochemical studies, appears superficially to be quite different from the human brain (Fig. 30-1), which is characterized by its large cerebral cortex. However, basic pathways are the same. Some major pathways for glutamate-secreting (glutamatergic) neurons are marked by arrows. Most of these originate in the neocortex (outer layers of the cerebral cortex) and the hippocampus. From Nicholls.149 Courtesy of David G. Nicholls.

Is there any evidence for deficits in subsets of hippocampal neurons Here, we will briefly review the evidence for an abnormality of the GABAergic and glutamatergic neurons in the hippocampus in schizophrenia (reviewed by others (Benes, 1999 Arnold, 2000 Benes and Berretta, 2001 Harrison and Eastwood, 2001 Harrison, 2004) and in this volume (Kristiansen et al.)). 

Squires RF, Lajtha A, Saederup E, Palkovits M. 1993. Reduced [3H]flunitrazepam binding in cingulate cortex and hippocampus of postmortem schizophrenic brains Is selective loss of glutamatergic neurons associated with major psychoses Neurochem Res 18 219-223. 

In parallel to the discovery of the long-term actions of dopamine on the sensitivity of the corticostriatal pathway, there have been a series of studies, which suggest that in the striatum, as in the hippocampus, the changes in synaptic strength have structural consequences. The earliest of these is probably the study of spine numbers in the neostriatum after destruction of dopamine input (Ingham et al., 1989). After a 6-OHDA lesion it seemed that there were fewer spines on individual dendrites in the striatum. The effect was visible as soon as the damage became stable at three weeks after the lesion and was still present one year later. But the lesion does not involve glutamatergic neurones. So perhaps the spines that are lost may have had dopamine synapses on them. That too seems unlikely since we estimated earlier that only about 11 % of spines would have a dopamine... 

The mammalian forebrain contains a subset of glutamatergic neurons that sequester zinc in their synaptic vesicles. Zinc-containing axon terminals are particularly abundant in the hippocampus," the piriform cortex, the neocortex, the striatum, and the amygdala (Figure 20.9). Cytosolic zinc is transported into vesicles by the... 

The brain is one of the sites that has been shown to be particularly sensitive to zinc deficiency during fetal development, with neural-tube defects and other disorders being found. While this work was performed in animals, a similar relationship appears likely in humans. Zinc is distributed throughout the brain, but greater concentrations are found within the hippocampus. Here, a brain-specific transporter, ZnT-3, concentrates zinc in vesicles within glutamatergic neurones. It is cosecreted with the neurotransmitter and appears to serve as a modulator of neurotransmission. Very... 

Hossain MM, Suzuki T, Unno T, Komori S, Kobayashi H (2008) Differential presynaptic actions of pyrethroid insecticides on glutamatergic and GABAergic neurons in the hippocampus. Toxicology 243 155-163... 

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