Biomaterial Database

Postnatal hippocampal granule cell agenesis in the rat: effects on two types of rhythmical slow activity (RSA) in two hippocampal generators. 1978

I Q Whishaw, and B H Bland, and S A Bayer

Hippocampal slow wave activity was studied in rats which were normal or had been subjected to denate gyrus granule cell agenesis by focal X-irradiation starting at birth (0-day group) or two days (2-day group) of age. X-irradiation reduced adult brain weight, abolished most (2-day) or all (0-day) granule cells in the lower (endal) blade of the dentate gyrus, and reduced granule cell density by up to 70% in the upper (ectal) blade of the dentate gyrus. X-irradiation did not affect pyramidal cells of the hippocampus proper. Tracking with microelectrodes in urethane anesthetized rats given eserine, sensory, or brain stimulation showed two foci of hippocampal rhythmical slow activity (theta or RSA), one in stratum oriens of CA1 and one in stratum moleculare of the dentate gyrus. These were opposite in phase by approximately 180 degrees and separated by a null zone and phase reversal point occurring at stratum radiatum. There were no significant differences in the amplitude, frequency, null, or phase reveral points in the normal or X-irradiated groups. However, the width of the RSA amplitude peak in the ectal blade was reduced, correlated with the reduction in the length of the ectal blade, and the RSA amplitude peak in the lower blade was absent, correlated with the absence of the lower blade. The fast activity recorded in the hilus of normal rats was absent in the X-irradiated groups. RSA recorded during spontaneous movement (walking) had identical amplitude, frequency, anatomical foci, and phase in both the hippocampus proper and dentate gyrus in normal and X-irradiated rats. Antimuscarinic, but not antinicotinic, agents abolished anesthesia-related RSA, but not movement-related RSA, in all groups of rats. The results are discussed in terms of their relevance to the two-generator hypothesis of RSA.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D009474	Neurons	The basic cellular units of nervous tissue. Each neuron consists of a body, an axon, and dendrites. Their purpose is to receive, conduct, and transmit impulses in the NERVOUS SYSTEM.	Nerve Cells,Cell, Nerve,Cells, Nerve,Nerve Cell,Neuron
D009929	Organ Size	The measurement of an organ in volume, mass, or heaviness.	Organ Volume,Organ Weight,Size, Organ,Weight, Organ
D011712	Pyramidal Tracts	Fibers that arise from cells within the cerebral cortex, pass through the medullary pyramid, and descend in the spinal cord. Many authorities say the pyramidal tracts include both the corticospinal and corticobulbar tracts.	Corticobulbar Tracts,Corticospinal Tracts,Decussation, Pyramidal,Corticobulbar Tract,Corticospinal Tract,Pyramidal Decussation,Pyramidal Tract,Tract, Corticobulbar,Tract, Corticospinal,Tract, Pyramidal,Tracts, Corticobulbar,Tracts, Corticospinal,Tracts, Pyramidal
D011950	Receptors, Cholinergic	Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology.	ACh Receptor,Acetylcholine Receptor,Acetylcholine Receptors,Cholinergic Receptor,Cholinergic Receptors,Cholinoceptive Sites,Cholinoceptor,Cholinoceptors,Receptors, Acetylcholine,ACh Receptors,Receptors, ACh,Receptor, ACh,Receptor, Acetylcholine,Receptor, Cholinergic,Sites, Cholinoceptive
D001931	Brain Mapping	Imaging techniques used to colocalize sites of brain functions or physiological activity with brain structures.	Brain Electrical Activity Mapping,Functional Cerebral Localization,Topographic Brain Mapping,Brain Mapping, Topographic,Functional Cerebral Localizations,Mapping, Brain,Mapping, Topographic Brain
D002452	Cell Count	The number of CELLS of a specific kind, usually measured per unit volume or area of sample.	Cell Density,Cell Number,Cell Counts,Cell Densities,Cell Numbers,Count, Cell,Counts, Cell,Densities, Cell,Density, Cell,Number, Cell,Numbers, Cell
D004569	Electroencephalography	Recording of electric currents developed in the brain by means of electrodes applied to the scalp, to the surface of the brain, or placed within the substance of the brain.	EEG,Electroencephalogram,Electroencephalograms
D006624	Hippocampus	A curved elevation of GRAY MATTER extending the entire length of the floor of the TEMPORAL HORN of the LATERAL VENTRICLE (see also TEMPORAL LOBE). The hippocampus proper, subiculum, and DENTATE GYRUS constitute the hippocampal formation. Sometimes authors include the ENTORHINAL CORTEX in the hippocampal formation.	Ammon Horn,Cornu Ammonis,Hippocampal Formation,Subiculum,Ammon's Horn,Hippocampus Proper,Ammons Horn,Formation, Hippocampal,Formations, Hippocampal,Hippocampal Formations,Hippocampus Propers,Horn, Ammon,Horn, Ammon's,Proper, Hippocampus,Propers, Hippocampus,Subiculums
D000200	Action Potentials	Abrupt changes in the membrane potential that sweep along the CELL MEMBRANE of excitable cells in response to excitation stimuli.	Spike Potentials,Nerve Impulses,Action Potential,Impulse, Nerve,Impulses, Nerve,Nerve Impulse,Potential, Action,Potential, Spike,Potentials, Action,Potentials, Spike,Spike Potential