Active Dendritic Integration of Inhibitory Synaptic Inputs In Vivo

2003 ◽  
Vol 90 (6) ◽  
pp. 3617-3624 ◽  
Author(s):  
Jason J. Kuo ◽  
Robert H. Lee ◽  
Michael D. Johnson ◽  
Heather M. Heckman ◽  
C. J. Heckman
Keyword(s):  
Spinal Cord ◽  
Lumbar Spinal Cord ◽  
Standard State ◽  
Dendritic Integration ◽  
Local Inhibition ◽  
Highly Active ◽  
Linear Integration ◽  
Inward Currents ◽  
Lumbar Spinal

Synaptic integration in vivo often involves activation of many afferent inputs whose firing patterns modulate over time. In spinal motoneurons, sustained excitatory inputs undergo enormous enhancement due to persistent inward currents (PICs) that are generated primarily in the dendrites and are dependent on monoaminergic neuromodulatory input from the brain stem to the spinal cord. We measured the interaction between dendritic PICs and inhibition generated by tonic electrical stimulation of nerves to antagonist muscles during voltage clamp in motoneurons in the lumbar spinal cord of the cat. Separate samples of cells were obtained for two different states of monoaminergic input: standard (provided by the decerebrate preparation, which has tonic activity in monoaminergic axons) and minimal (the chloralose anesthetized preparation, which lacks tonic monoaminergic input). In the standard state, steady inhibition that increased the input conductance of the motoneurons by an average of 38% reduced the PIC by 69%. The range of this reduction, from <10% to >100%, was proportional to the magnitude of the applied inhibition. Thus nearly linear integration of synaptic inhibition may occur in these highly active dendrites. In the minimal state, PICs were much smaller, being approximately equal to inhibition-suppressed PICs in the standard state. Inhibition did not further reduce these already small PICs. Overall, these results demonstrate that inhibition from local spinal circuits can oppose the facilitation of dendritic PICs by descending monoaminergic inputs. As a result, local inhibition may also suppress active dendritic integration of excitatory inputs.

scholarly journals Characterization of DTI Indices in the Cervical, Thoracic, and Lumbar Spinal Cord in Healthy Humans

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Rachael L. Bosma ◽  
Patrick W. Stroman
Keyword(s):  
Spinal Cord ◽  
Mean Diffusivity ◽  
Lumbar Spinal Cord ◽  
Single Shot ◽  
Tissue Properties ◽  
Healthy Humans ◽  
Diffusion Weighted Images ◽  
Lumbar Spinal

The aim of this study was to characterizein vivomeasurements of diffusion along the length of the entire healthy spinal cord and to compare DTI indices, including fractional anisotropy (FA) and mean diffusivity (MD), between cord regions. The objective is to determine whether or not there are significant differences in DTI indices along the cord that must be considered for future applications of characterizing the effects of injury or disease. A cardiac gated, single-shot EPI sequence was used to acquire diffusion-weighted images of the cervical, thoracic, and lumbar regions of the spinal cord in nine neurologically intact subjects (19 to 22 years). For each cord section, FA versus MD values were plotted, and a k-means clustering method was applied to partition the data according to tissue properties. FA and MD values from both white matter (averageFA=0.69, averageMD=0.93×10−3 mm2/s) and grey matter (averageFA=0.44, averageMD=1.8×10−3 mm2/s) were relatively consistent along the length of the cord.

scholarly journals In Vivo Electrophysiology of Peptidergic Neurons in Deep Layers of the Lumbar Spinal Cord after Optogenetic Stimulation of Hypothalamic Paraventricular Oxytocin Neurons in Rats

2021 ◽  
Vol 22 (7) ◽  
pp. 3400
Author(s):  
Daisuke Uta ◽  
Takumi Oti ◽  
Tatsuya Sakamoto ◽  
Hirotaka Sakamoto
Keyword(s):  
Spinal Cord ◽  
Electrical Response ◽  
Oxytocin Receptor ◽  
Lumbar Spinal Cord ◽  
Whole Cell ◽  
Optogenetic Stimulation ◽  
Lumbar Spinal ◽  
Whole Cell Recordings ◽  
Stimulation Of

The spinal ejaculation generator (SEG) is located in the central gray (lamina X) of the rat lumbar spinal cord and plays a pivotal role in the ejaculatory reflex. We recently reported that SEG neurons express the oxytocin receptor and are activated by oxytocin projections from the paraventricular nucleus of hypothalamus (PVH). However, it is unknown whether the SEG responds to oxytocin in vivo. In this study, we analyzed the characteristics of the brain–spinal cord neural circuit that controls male sexual function using a newly developed in vivo electrophysiological technique. Optogenetic stimulation of the PVH of rats expressing channel rhodopsin under the oxytocin receptor promoter increased the spontaneous firing of most lamina X SEG neurons. This is the first demonstration of the in vivo electrical response from the deeper (lamina X) neurons in the spinal cord. Furthermore, we succeeded in the in vivo whole-cell recordings of lamina X neurons. In vivo whole-cell recordings may reveal the features of lamina X SEG neurons, including differences in neurotransmitters and response to stimulation. Taken together, these results suggest that in vivo electrophysiological stimulation can elucidate the neurophysiological response of a variety of spinal neurons during male sexual behavior.

scholarly journals Involvement of cannabinoid type 1 receptor in fasting-induced analgesia

2020 ◽  
Vol 16 ◽  
pp. 174480692096947
Author(s):  
Jeong-Yun Lee ◽  
Grace J. Lee ◽  
Ayumi Nakamura ◽  
Pa Reum Lee ◽  
Yeajin Kim ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Endocannabinoid System ◽  
Lumbar Spinal Cord ◽  
Peripheral Tissues ◽  
Cannabinoid Type 1 Receptor ◽  
Analgesic Effects ◽  
Sr 141716 ◽  
Lumbar Spinal

The endocannabinoid system (ECS) is known to modulate not only food intake but also pain, especially via the cannabinoid type 1 receptor (CB1R) expressed throughout the central nervous system and the peripheral tissues. Our previous study demonstrated that fasting produces an analgesic effect in adult male mice, which is reversed by intraperitoneal (i.p.) administration of CB1R antagonist (SR 141716). In the present study, we further examined the effect of CB1R expressed in the peripheral tissues. In the formalin-induced inflammatory pain model, i.p. administration of peripherally restricted CB1R antagonist (AM 6545) reversed fasting-induced analgesia. However, intraplantar administration of SR 141716 did not affect fasting-induced analgesia. Furthermore, mRNA expression of CB1R did not change in the formalin model by fasting in the dorsal root ganglia. The formalin-induced c-Fos expression at the spinal cord level was not affected by fasting, and in vivo recording from the superficial dorsal horn of the lumbar spinal cord revealed that fasting did not affect formalin-induced neural activity, which indicates minimal involvement of the spinal cord in fasting-induced analgesia. Finally, when we performed subdiaphragmatic vagotomy to block the hunger signal from the gastrointestinal (GI) system, AM 6545 did not affect fasting-induced analgesia, but SR 141716 still reversed fasting-induced analgesia. Taken together, our results suggest that both peripheral and central CB1Rs contribute to fasting-induced analgesic effects and the CB1Rs in the GI system which transmit fasting signals to the brain, rather than those in the peripheral sensory neurons, may contribute to fasting-induced analgesic effects.

scholarly journals In Vivo Recording of Nerve Conduction Velocity of Spinal CNS Fibers in the Mouse

2017 ◽  
pp. 545-548
Author(s):  
P. DIBAJ ◽  
E. D. SCHOMBURG
Keyword(s):  
Spinal Cord ◽  
Conduction Velocity ◽  
Nerve Conduction ◽  
Nerve Conduction Velocity ◽  
Compound Action Potential ◽  
Lumbar Spinal Cord ◽  
Measured Distance ◽  
Spinal Cord Level ◽  
Lumbar Spinal

Anesthetic and surgical procedures and an electrophysiological method were developed for recording nerve conduction velocity (NCV) of CNS fibers in the murine spinal cord. Under intravenous anesthesia and artificial ventilation the lumbar spinal cord segments L1 to L4 and dorsal roots L3 to L5 on the left side were exposed by laminectomy. After stimulation of the dorsal root L4, a compound action potential (CAP) was recorded at the ipsilateral left fasciculus gracilis at the spinal cord level L1. The latency from stimulation to the CAP together with the measured distance between the electrodes was used for the determination of the NCV. NCV of the fastest fibers in the fasciculus gracilis was observed to be approximately 28 m/s. Reversible decrease of the NCV was measured, in vivo, under general hypothermia. The technique described serves for in vivo electrophysiological investigations of spinal central fibers in wildtype and mutant mice.

scholarly journals Effects of Glutamate andγ-Aminobutyric Acid on Spontaneously Active Intraocular Spinal Cord Graft Neurons

1991 ◽  
Vol 2 (2) ◽  
pp. 101-111
Author(s):  
J. G. Broton ◽  
R. P. Yezierski ◽  
Å. Seiger
Keyword(s):  
Spinal Cord ◽  
Firing Rate ◽  
Gaba Receptor ◽  
Aminobutyric Acid ◽  
Lumbar Spinal Cord ◽  
Adult Rat ◽  
Fetal Rat ◽  
Single Unit Recordings ◽  
Lumbar Spinal

Pieces of fetal rat lumbar spinal cord were transplanted into the anterior eye chamber of adult rat hosts. At least seven months later, extracellular single-unit recordings of spontaneously active graft neurons were made prior to and during the superfusion of either glutamate orγ-aminobutyric acid (GABA). Superfusion of glutamate produced an increase (five cells), decrease (three cells), or had no effect (two cells) on the firing rate of neurons tested. Superfusion of GABA decreased the firing rate of all twelve neurons tested, while superfusion of the GABA receptor antagonist bicuculline increased the firing rates of all eight neurons tested. The latency and magnitude of the responses to glutamate and GABA were not related to depth of the recording electrode below the graft surface. Together, these data suggest that the intraocular spinal cord graft is suitable for thein vivostudy of GABA and glutamate neuropharmacology.

Acetylcholine release from fetal tissue homotopically grafted to the motoneuron-depleted lumbar spinal cord. An in vivo microdialysis study in the awake rat

2007 ◽  
Vol 204 (1) ◽  
pp. 326-338 ◽  
Author(s):  
Rosario Gulino ◽  
Tiziana Cataudella ◽  
Fiorella Casamenti ◽  
Giancarlo Pepeu ◽  
Stefania Stanzani ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Acetylcholine Release ◽  
Fetal Tissue ◽  
In Vivo Microdialysis ◽  
Lumbar Spinal Cord ◽  
Awake Rat ◽  
Microdialysis Study ◽  
Lumbar Spinal

scholarly journals Pruriceptive spinothalamic tract neurons: physiological properties and projection targets in the primate

2012 ◽  
Vol 108 (6) ◽  
pp. 1711-1723 ◽  
Author(s):  
Steve Davidson ◽  
Xijing Zhang ◽  
Sergey G. Khasabov ◽  
Hannah R. Moser ◽  
Christopher N. Honda ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Receptive Field ◽  
Dorsal Horn ◽  
Information Transfer ◽  
Lumbar Spinal Cord ◽  
Thalamic Nuclei ◽  
Spinothalamic Tract ◽  
Medial Geniculate ◽  
Lumbar Spinal

Itch of peripheral origin requires information transfer from the spinal cord to the brain for perception. Here, primate spinothalamic tract (STT) neurons from lumbar spinal cord were functionally characterized by in vivo electrophysiology to determine the role of these cells in the transmission of pruriceptive information. One hundred eleven STT neurons were identified by antidromic stimulation and then recorded while histamine and cowhage (a nonhistaminergic pruritogen) were sequentially applied to the cutaneous receptive field of each cell. Twenty percent of STT neurons responded to histamine, 13% responded to cowhage, and 2% responded to both. All pruriceptive STT neurons were mechanically sensitive and additionally responded to heat, intradermal capsaicin, or both. STT neurons located in the superficial dorsal horn responded with greater discharge and longer duration to pruritogens than STT neurons located in the deep dorsal horn. Pruriceptive STT neurons discharged in a bursting pattern in response to the activating pruritogen and to capsaicin. Microantidromic mapping was used to determine the zone of termination for pruriceptive STT axons within the thalamus. Axons from histamine-responsive and cowhage-responsive STT neurons terminated in several thalamic nuclei including the ventral posterior lateral, ventral posterior inferior, and posterior nuclei. Axons from cowhage-responsive neurons were additionally found to terminate in the suprageniculate and medial geniculate nuclei. Histamine-responsive STT neurons were sensitized to gentle stroking of the receptive field after the response to histamine, suggesting a spinal mechanism for alloknesis. The results show that pruriceptive information is encoded by polymodal STT neurons in histaminergic or nonhistaminergic pathways and transmitted to the ventrobasal complex and posterior thalamus in primates.

Lipomeningocele associated with diplomyelia in a dog

2018 ◽  
Vol 46 (05) ◽  
pp. 323-329 ◽  
Author(s):  
Nele Ondreka ◽  
Sara Malberg ◽  
Emma Laws ◽  
Martin Schmidt ◽  
Sabine Schulze
Keyword(s):  
Spinal Cord ◽  
Neurological Status ◽  
Split Cord Malformation ◽  
Lumbar Spinal Cord ◽  
Histopathological Diagnosis ◽  
Type I ◽  
Thoracic Spinal Cord ◽  
Thoracic Spinal ◽  
Subcutaneous Mass ◽  
Lumbar Spinal

SummaryA 2-year-old male neutered mixed breed dog with a body weight of 30 kg was presented for evaluation of a soft subcutaneous mass on the dorsal midline at the level of the caudal thoracic spine. A further clinical sign was intermittent pain on palpation of the area of the subcutaneous mass. The owner also described a prolonged phase of urination with repeated interruption and re-initiation of voiding. The findings of the neurological examination were consistent with a lesion localization between the 3rd thoracic and 3rd lumbar spinal cord segments. Magnetic resonance imaging revealed a spina bifida with a lipomeningocele and diplomyelia (split cord malformation type I) at the level of thoracic vertebra 11 and 12 and secondary syringomyelia above the aforementioned defects in the caudal thoracic spinal cord. Surgical resection of the lipomeningocele via a hemilaminectomy was performed. After initial deterioration of the neurological status postsurgery with paraplegia and absent deep pain sensation the dog improved within 2 weeks to non-ambulatory paraparesis with voluntary urination. Six weeks postoperatively the dog was ambulatory, according to the owner. Two years after surgery the owner recorded that the dog showed a normal gait, a normal urination and no pain. Histopathological diagnosis of the biopsied material revealed a lipomeningocele which confirmed the radiological diagnosis.

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