Activation and circuitry of uterine-cervix-related neurons in the lumbosacral dorsal root ganglia and spinal cord at parturition.
Analysis of Variance; Animals; Blotting; Cell Count/methods; Cervix Uteri/*cytology; Cyclic AMP Response Element-Binding Protein/metabolism; Estrogen Receptor alpha/metabolism; Female; Ganglia; Gene Expression Regulation/physiology; Immunohistochemistry/methods; Lumbosacral Region; Models; Nerve Net/cytology/*physiology; Neurological; Neurons/classification/*physiology; Oncogene Proteins v-fos/metabolism; Parturition/*physiology; Pregnancy; Rats; Spinal Cord/*cytology; Spinal/*cytology; Sprague-Dawley; Stilbamidines/metabolism; Time Factors; Western/methods
Stimulation of the uterine cervix at parturition activates neural circuits involving primary sensory nerves and supraspinally projecting neurons of the lumbosacral spinal cord, resulting in output of hypothalamic neurohormones. Dorsal root ganglia (DRG) and spinal neurons of these circuits are not well-characterized. The objectives of this study were to detail the activation of DRG and spinal neurons of the L6/S1 levels that are stimulated at late pregnancy, verify hypothalamic projections of activated spinal neurons, and determine whether activated neurons express estrogen receptor-alpha (ERalpha). Expression of phosphorylated cyclic-AMP response element-binding protein (PCREB) and Fos immunohistochemistry were used to "mark" activated DRG and spinal neurons, respectively. Retrograde tracing identified uterine-cervix-related and spinohypothalamic neurons. Baseline PCREB expression in the DRG increased during pregnancy and peaked during the last trimester. Some PCREB-expressing neurons contained retrograde tracer identifying them as cervix-related neurons. Fos-expressing neurons were few in spinal cords of nonpregnant and day 22 pregnant rats but were numerous in parturient animals. Some Fos-expressing neurons located in the dorsal half of the spinal cord contained retrograde tracer identifying them as spinohypothalamic neurons. Some DRG neurons expressing PCREB also expressed ERalpha, and some spinal neurons activated at parturition projected axons to the hypothalamus and expressed ERalpha. These results indicate that DRG and spinal cord neurons are activated at parturition; that those in the spinal cord are present in areas involved in autonomic and sensory processing; that some spinal neurons project axons to the hypothalamus, ostensibly part of a neuroendocrine reflex; and that sensory and spinal neurons can respond to estrogens. Moreover, some activated sensory neurons may be involved in the animal's perception of labor pain.
Puder B A; Papka R E
Journal of neuroscience research
2005
2005-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1002/jnr.20690" target="_blank" rel="noreferrer noopener">10.1002/jnr.20690</a>
Use of brain slices to study long-term potentiation and depression as examples of synaptic plasticity.
*Long-Term Potentiation; *Neuronal Plasticity; Animals; Brain/*physiology; Electrophysiology/methods; Glutamic Acid/physiology; In Vitro Techniques; Memory/*physiology; Models; Neurological; Synapses/*physiology; Synaptic Transmission
Brain slices have been responsible for the majority of advances in our understanding of the cellular aspects of altered synaptic strength underlying memory, long-term potentiation (LTP) and long-term depression (LTD), and increases and decreases, respectively, in synaptic strength at glutamatergic synapses. Our current understanding of LTP and LTD has come largely from studies in hippocampal slices. We consider the strengths and limitations of brain slice technology applied to this subject and conclude that they will continue to have an important role in future studies into the cellular machinery underlying changes in synaptic strength.
Teyler T J
Methods (San Diego, Calif.)
1999
1999-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1006/meth.1999.0764" target="_blank" rel="noreferrer noopener">10.1006/meth.1999.0764</a>
Synaptic plasticity in the hippocampal slice: functional consequences.
Animals; Calcium Channels/physiology; Hippocampus/*physiology; Long-Term Potentiation/physiology; Models; N-Methyl-D-Aspartate/physiology; Neurological; Neuronal Plasticity/*physiology; Receptors; Synapses/*physiology
There are 3 known forms of synaptic plasticity at CNS synapses: long-term potentiation (LTP) mediated by NMDA receptor activation, LTP mediated by voltage-dependent calcium channel (VDCC) activation, and long-term depression (LTD) mediated by the NMDA receptor. All 3 forms of synaptic plasticity can be observed in hippocampal CAl cells, all are induced by afferent activation, all involve Ca2+ influx, and all activate Ca(2+)-dependent mechanisms. We consider the functional consequences of the presence of 3, sometime opposing, forms of synaptic plasticity at the same synapse. We suggest that the 2 forms of LTP have different consequences for the synapse. We postulate that the co-existence of potentiating and depressing capabilities influences the network processing capabilities of neural networks.
Teyler T J; Cavus I; Coussens C
Journal of neuroscience methods
1995
1995-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0165-0270(94)00188-m" target="_blank" rel="noreferrer noopener">10.1016/0165-0270(94)00188-m</a>
Neural processing of target distance by echolocating bats: functional roles of the auditory midbrain.
Animals; Auditory Cortex/physiology; Auditory Pathways/*physiology; Auditory Perception/*physiology; Brain Mapping/psychology; Chiroptera/*physiology; Echolocation/*physiology; Inferior Colliculi/*physiology; Models; Neurological; Neurons/physiology
Using their biological sonar, bats estimate distance to avoid obstacles and capture moving prey. The primary distance cue is the delay between the bat's emitted echolocation pulse and the return of an echo. The mustached bat's auditory midbrain (inferior colliculus, IC) is crucial to the analysis of pulse-echo delay. IC neurons are selective for certain delays between frequency modulated (FM) elements of the pulse and echo. One role of the IC is to create these "delay-tuned", "FM-FM" response properties through a series of spectro-temporal integrative interactions. A second major role of the midbrain is to project target distance information to many parts of the brain. Pathways through auditory thalamus undergo radical reorganization to create highly ordered maps of pulse-echo delay in auditory cortex, likely contributing to perceptual features of target distance analysis. FM-FM neurons in IC also project strongly to pre-motor centers including the pretectum and the pontine nuclei. These pathways may contribute to rapid adjustments in flight, body position, and sonar vocalizations that occur as a bat closes in on a target.
Wenstrup Jeffrey J; Portfors Christine V
Neuroscience and biobehavioral reviews
2011
2011-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/j.neubiorev.2010.12.015" target="_blank" rel="noreferrer noopener">10.1016/j.neubiorev.2010.12.015</a>
Construction of a model demonstrating neural pathways and reflex arcs.
*Models; Animals; Education; Medical; Neural Pathways/*physiology; Neurological; Reflex/*physiology
Employment opportunities in the future will require higher skills and an understanding of mathematics and science. As a result of the growing number of careers that require solid science and mathematics training, the methods of science education are undergoing major reform. To adequately equip students for technologically advanced positions, new teaching methods must be developed that prepare tomorrow's workforce for the challenges of the 21st century. One such method is the use of models. By actively building and manipulating concrete models that represent scientific concepts, students are involved in the most basic level of Piaget's learning scheme: the sensorimotor stage. Models are useful in reaching all students at the foundational levels of learning, and further learning experiences are rapidly moved through higher learning levels. This success ensures greater comprehension and understanding compared with the traditional methods of rote memorization. We developed an exercise for the construction of an inexpensive, easy-to-build model demonstrating neural pathways and reflex arcs. Our exercise also includes many supplemental teaching tools. The exercise is designed to fulfill the need of sound physiological teaching materials for high school students.
Chan V; Pisegna J M; Rosian R L; DiCarlo S E
The American journal of physiology
1996
1996-12
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/advances.1996.271.6.S14" target="_blank" rel="noreferrer noopener">10.1152/advances.1996.271.6.S14</a>
Endogenous mGluR activity suppresses GABAergic transmission in avian cochlear nucleus magnocellularis neurons.
2-Amino-5-phosphonovalerate/pharmacology; Amino Acids/pharmacology; Animals; Chickens/*physiology; Cochlear Nucleus/*cytology/*physiology; Electric Stimulation; Excitatory Amino Acid Antagonists/pharmacology; Excitatory Postsynaptic Potentials/physiology; GABA-B Receptor Agonists; GABA-B Receptor Antagonists; GABA-B/physiology; gamma-Aminobutyric Acid/*physiology; Glycine/analogs & derivatives/pharmacology; In Vitro Techniques; Kinetics; Membrane Potentials/drug effects; Metabotropic Glutamate/agonists/antagonists & inhibitors/*metabolism/physiology; Models; Neurological; Neurons/*physiology; Patch-Clamp Techniques; Receptors; Resorcinols/pharmacology; Synapses/physiology; Synaptic Transmission/*physiology; Xanthenes/pharmacology
GABAergic transmission in the avian cochlear nucleus magnocellularis (NM) of the chick is subject to modulation by gamma-aminobutyric acid type B (GABA(B)) autoreceptors. Here, I investigated modulation of GABAergic transmission in NM by metabotropic glutamate receptors (mGluRs) with whole cell recordings in brain slice preparations. I found that tACPD, a nonspecific mGluR agonist, exerted dose-dependent suppression on evoked inhibitory postsynaptic currents (eIPSCs) in NM neurons. At concentrations of 100 or 200 microM, tACPD increased the failure rate of GABAergic transmission. Agonists for group I (3,5-DHPG, 200 microM), group II (DCG-IV, 2 microM), and group III (L-AP4, 10 microM) mGluRs produced a significant reduction in the amplitude of eIPSCs and a significant increase in failure rate, indicating the involvement of multiple mGluRs in this modulation. The frequency, but not the amplitude, of miniature IPSCs (mIPSCs) was decreased significantly by 3,5-DHPG or DCG-IV. Neither frequency nor amplitude of mIPSCs was affected by L-AP4. mGluR antagonists LY341495 (20 microM) plus CPPG (10 microM) significantly increased the amplitude of eIPSCs, indicating that endogenous mGluR activity suppresses GABA release to NM neurons. Furthermore, blockage of mGluRs increased GABA-evoked discharges recorded under physiological Cl(-) concentrations, whereas tACPD (100 microM) eliminated them. The results indicate that mGluRs play important roles in achieving balanced excitation and inhibition in NM and preserving fidelity of temporal information encoded by NM neurons.
Lu Yong
Journal of neurophysiology
2007
2007-02
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.00883.2006" target="_blank" rel="noreferrer noopener">10.1152/jn.00883.2006</a>
Roles of inhibition in creating complex auditory responses in the inferior colliculus: facilitated combination-sensitive neurons.
Acoustic Stimulation/methods; Action Potentials/*physiology; Animals; Auditory Pathways/physiology; Bicuculline/pharmacology; Cell Count; Drug Interactions; GABA Antagonists/pharmacology; Glycine Agents/pharmacology; Inferior Colliculi/*cytology; Iontophoresis/methods; Models; Neural Inhibition/drug effects/*physiology; Neurological; Neurons/classification/drug effects/*physiology/radiation effects; Otters; Reaction Time/*physiology/radiation effects; Regression Analysis; Strychnine/pharmacology; Time Factors; Wakefulness/physiology
We studied roles of inhibition on temporally sensitive facilitation in combination-sensitive neurons from the mustached bat's inferior colliculus (IC). In these integrative neurons, excitatory responses to best frequency (BF) tones are enhanced by much lower frequency signals presented in a specific temporal relationship. Most facilitated neurons (76%) showed inhibition at delays earlier than or later than the delays causing facilitation. The timing of inhibition at earlier delays was closely related to the best delay of facilitation, but the inhibition had little influence on the duration or strength of the facilitatory interaction. Local iontophoretic application of antagonists to receptors for glycine (strychnine, STRY) and gamma-aminobutyric acid (GABA) (bicuculline, BIC) showed that STRY abolished facilitation in 96% of tested units, but BIC eliminated facilitation in only 28%. This suggests that facilitatory interactions are created in IC and reveals a differential role for these neurotransmitters. The facilitation may be created by coincidence of a postinhibitory rebound excitation activated by the low-frequency signal with the BF-evoked excitation. Unlike facilitation, inhibition at earlier delays was not eliminated by application of antagonists, suggesting an origin in lower brain stem nuclei. However, inhibition at delays later than facilitation, like facilitation itself, appears to originate within IC and to be more dependent on glycinergic than GABAergic mechanisms. Facilitatory and inhibitory interactions displayed by these combination-sensitive neurons encode information within sonar echoes and social vocalizations. The results indicate that these complex response properties arise through a series of neural interactions in the auditory brain stem and midbrain.
Nataraj Kiran; Wenstrup Jeffrey J
Journal of neurophysiology
2005
2005-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.01152.2004" target="_blank" rel="noreferrer noopener">10.1152/jn.01152.2004</a>
Hyperpolarizing and depolarizing GABAA receptor-mediated dendritic inhibition in area CA1 of the rat hippocampus.
2-Amino-5-phosphonovalerate/pharmacology; Animals; Bicuculline/analogs & derivatives/pharmacology; Chlorides/pharmacology; Dendrites/drug effects/*physiology; Evoked Potentials/drug effects; GABA-A Receptor Antagonists; GABA-A/drug effects/*physiology; Hippocampus/*physiology; In Vitro Techniques; Kinetics; Mathematics; Membrane Potentials/drug effects; Models; Neurological; Neurons/drug effects/*physiology; Organophosphorus Compounds/pharmacology; Pyramidal Tracts/drug effects/*physiology; Quinoxalines/pharmacology; Rats; Receptors; Synapses/drug effects/physiology
1. gamma-Aminobutyric acidA (GABAA) receptor-mediated inhibition of pyramidal neuron dendrites was studied in area CA1 of the rat hippocampal slice preparation with the use of intracellular and extracellular recording and one-dimensional current source-density (CSD) analysis. 2. Electrical stimulation of Schaffer collateral/commissural fibers evoked monosynaptic excitatory postsynaptic potentials (EPSPs) and population EPSPs, which were followed by biphasic inhibitory postsynaptic potentials (IPSPs). In the presence of the excitatory amino acid receptor antagonists 6,7-dinitroquinoxaline-2,3-dione (DNQX) and D,L-2-amino-5-phosphonovalerate (APV), stimulation in stratum radiatum evoked monosynaptic fast, GABAA and late, GABAB receptor-mediated IPSPs and fast and late positive field potentials recorded in s. radiatum. 3. Fast monosynaptic IPSPs and fast positive field potentials evoked in the presence of DNQX and APV were reversibly abolished by the GABAA receptor antagonist bicuculline methiodide (BMI; 30 microM) and were not changed by the GABAB receptor antagonist
Lambert N A; Borroni A M; Grover L M; Teyler T J
Journal of neurophysiology
1991
1991-11
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1152/jn.1991.66.5.1538" target="_blank" rel="noreferrer noopener">10.1152/jn.1991.66.5.1538</a>
A method for calculating current source density (CSD) analysis without resorting to recording sites outside the sampling volume.
Animals; Electric Stimulation; Action Potentials; Visual Cortex/*physiology; Neurophysiology/*methods; Photic Stimulation; Models; Neurological
This article is part of a study on cortical microcircuitry in which flash evoked potentials (FEPs) were recorded from the anesthetized rat visual cortex. The FEPs were subjected to current source density analysis (CSD). One of the limitations of the CSD method is the need for recording sites outside the sampling volume, in order to obtain a full description of the CSD distribution. This problem is acute in the neocortex where a tissue/fluid boundary exists. A simple solution is provided based on the fact that the field potentials decay minimally under the conditions of these experiments. In the neocortex the most superficial recording site and the deepest recording site are used to provide the extra recording sites necessary to obtain a full description of the CSD distribution. This approach when tested by summing the current sinks and sources across all layers of cortex produces excellent results, with significant reduction of the residual sinks and sources.
Vaknin G; DiScenna P G; Teyler T J
Journal of neuroscience methods
1988
1988-06
Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).
<a href="http://doi.org/10.1016/0165-0270(88)90056-8" target="_blank" rel="noreferrer noopener">10.1016/0165-0270(88)90056-8</a>