Electrical Interactions Between Mammalian Cortical Neurons
Abstract
This research has been aimed at understanding basic mechanisms of neuronal communication in the mammalian brain. The work has focused on rapid mechanisms of electrical and synaptic transmission with an emphasis on local circuits. Much of our research has dealt with electrical interactions between hippocampal neurons, but recently we have also studied mechanisms of excitatory and inhibitory synaptic transmission in the hypothalamus. In the hippocampus, alterations in the osmolality of the extracellular fluid greatly modified the synchronous bursts of population spikes that occur in low calciumion (Ca2+) solutions (i.e., with chemical synapses blocked ). Increases in osmolality reduced or blocked the spontaneous bursts, and decreases in osmolality had the opposite effect. Since these changes in osmolality (10-20%) would be expected to cause cell shrinkage or swelling, modifications in the strength of ephaptic transmission probably mediate or contribute significantly to these effects. Studies in the hypothalamus have primarily addressed the role of excitatory amino acids (EAAs) in fast synaptic transmission in the supraoptic and paraventricular nuclei. Kynurenic acid and delfa-D-glutamyglycine (broad- spectrum EAA antagonists) reduced EPSPs in supraoptic neurons, while N-methyl-D- aspartate (NMDA) antagonists had relatively little effect on EPSPs. We have initiated studies on local synaptic circuits among hypothalamic neurons.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 28, 1988
- Accession Number
- ADA203192
Entities
People
- F. E. Dudek
Organizations
- UCLA David Geffen School of Medicine