Physiological properties of sympathetic preganglionic neurones in the thoracic intermediolateral nucleus of the cat

1984 ◽  
Vol 62 (9) ◽  
pp. 1183-1193 ◽  
Author(s):  
Steven B. Backman ◽  
James L. Henry
Keyword(s):  
Interstimulus Interval ◽  
Functional Differentiation ◽  
Periodic Pattern ◽  
Antidromic Activation ◽  
Basal Activity ◽  
Physiological Properties ◽  
Irregular Pattern ◽  
Spinal Segments ◽  
Antidromic Response ◽  
Intermediolateral Nucleus

Extracellular spikes were recorded from cell bodies of sympathetic preganglionic neurones in spinal segments T1–T3 of the cat. Each neurone was identified by its antidromic response to electrical stimulation of the sympathetic chain and was found in histological sections to lie within the intermediolateral nucleus. Physiological properties studied in detail included basal activity, spike configuration, and latency of antidromic activation. Also studied, in tests with paired stimuli, were the threshold interstimulus interval evoking two responses, as well as changes in amplitude and latency of the second spike which occurred at intervals near this threshold. Approximately 60% of the units studied were spontaneously active, the rest were silent. Spontaneous activity was characterized by a slow ([Formula: see text] (SD) spikes/s), irregular pattern of discharge. With approximately one-third of the cases there was a periodic pattern of discharge in phase with oscillations in blood pressure. This correlation of phasic activity suggests that many of the units studied were involved specifically in cardiovascular function. Silent and spontaneously active units could not be differentiated on the basis of latency of antidromic activation or threshold interstimulus interval; mean latency for the two groups was 7.2 ± 4.9 ms, mean threshold interval was 6.4 ± 4.7 ms. Thus, with the exception of basal activity, the physiological properties studied failed to indicate more than a single population of neurones. These results therefore suggest that the sympathetic preganglionic neurones in the intermediolateral nucleus subserving varied autonomic functions share overlapping physiological properties, and that functional differentiation of these neurones may be based on differences in synaptic inputs.

Adrenal versus nonadrenal sympathetic preganglionic neurones in the lower thoracic intermediolateral nucleus of the cat: physiological properties

1990 ◽  
Vol 68 (11) ◽  
pp. 1447-1456 ◽  
Author(s):  
S. B. Backman ◽  
H. Sequeira-Martinho ◽  
J. L. Henry
Keyword(s):  
Electrical Stimulation ◽  
Adrenal Medulla ◽  
Splanchnic Nerve ◽  
Physiological Properties ◽  
Preganglionic Neurone ◽  
Spinal Segments ◽  
The Mean ◽  
Greater Splanchnic Nerve ◽  
Intermediolateral Nucleus ◽  
Stimulation Of

Adrenal and nonadrenal sympathetic preganglionic neurones (SPNs) in the intermediolateral nucleus of spinal segments T8–T10 in the cat were compared according to a number of physiological properties. An SPN was classified as "adrenal" (n = 37) if it could be antidromically activated by electrical stimulation of the adrenal medulla. An SPN that could not be activated from the adrenal medulla yet could be antidromically activated by electrical stimulation of the greater splanchnic nerve was classified as "nonadrenal" (n = 123). Approximately 50% of adrenal SPNs (17 out of 37) were activated antidromically by stimulation of both the greater splanchnic nerve and adrenal medulla, suggesting that these neurones projected to the adrenal medulla via the greater splanchnic nerve, with the other adrenal SPNs taking a different route. The mean conduction velocities of adrenal (6.7 ± 1.8 (SD) m/s) and nonadrenal (6.7 ± 1.5 m/s) sympathetic preganglionic axons were similar. Over 80% of adrenal (31 out of 37) and nonadrenal (104 out of 116) SPNs were spontaneously active. The two types of neurone were indistinguishable in terms of the rates and patterns of discharge. Adrenal SPNs discharged with a mean rate of 1.4 ± 1.1 spikes/s, and nonadrenal SPNs discharged with a mean rate of 1.8 ± 1.4 spikes/s. With both types of SPN, the pattern of spontaneous activity was either irregular or phasic. With the latter pattern, periodic bursts of discharge were at the same frequency as oscillations in arterial pressure, frequency of ventilation, or phrenic nerve discharge. These data suggest that adrenal and nonadrenal sympathetic preganglionic neurones in the intermediolateral nucleus in caudal thoracic segments share a number of common physiological properties.Key words: adrenal, sympathetic preganglionic neurone, spinal cord, lateral horn.

Effects of substance P and thyrotropin-releasing hormone on sympathetic preganglionic neurones in the upper thoracic intermediolateral nucleus of the cat

1984 ◽  
Vol 62 (2) ◽  
pp. 248-251 ◽  
Author(s):  
S. B. Backman ◽  
J. L. Henry
Keyword(s):  
Substance P ◽  
Synaptic Transmission ◽  
Thyrotropin Releasing Hormone ◽  
Excitatory Effect ◽  
Releasing Hormone ◽  
Spinal Segments ◽  
Time Courses ◽  
Upper Thoracic ◽  
Intermediolateral Nucleus ◽  
Chemical Mediators

When applied by iontophoresis onto single sympathetic preganglionic neurones in the intermediolateral nucleus of spinal segments T1–T3 in the cat, substance P and thyrotropin-releasing hormone (TRH) each had a weak excitatory effect. Two-thirds of the neurones studied were excited by substance P while one-fifth were excited by TRH. The time courses of the responses to substance P and to TRH were similar, and consisted of an increase in the rate of discharge with a latency of approximately 30 s from the onset of application. They were also prolonged (30–320 s) in afterdischarge following termination of application. These results indicate that substance P and TRH exert excitatory effects on single sympathetic preganglionic neurones, and support the possibility that they may be chemical mediators of synaptic transmission in the intermediolateral nucleus.

Microstimulation of the primate neostriatum. I. Physiological properties of striatal microexcitable zones

1985 ◽  
Vol 53 (6) ◽  
pp. 1401-1416 ◽  
Author(s):  
G. E. Alexander ◽  
M. R. DeLong
Keyword(s):  
Motor Response ◽  
Internal Capsule ◽  
Ibotenic Acid ◽  
Body Parts ◽  
Antidromic Activation ◽  
Orofacial Movements ◽  
Stimulus Current ◽  
Physiological Properties ◽  
Current Spread ◽  
Output Neurons

Microstimulation was carried out at over 1,250 sites in the putamen in four unanesthetized rhesus monkeys. At numerous sites, microstimulation resulted in movements of individual body parts including leg, arm, and face. Microstimulation-evoked limb movements were invariably contralateral to the stimulating electrode. In nearly all instances, the response at threshold was restricted to or maximal about a single joint. A small percentage of stimulation-evoked axial and orofacial movements were bilateral. The same motor response was frequently evoked over distances of up to 1,200 micron along a single penetration, suggesting that a relatively homogeneous motor-response zone underlies the observed micro-stimulation effects. We have designated these presumptive functional units striatal microexcitable zones (SMZ). The boundaries of adjacent SMZ involved in different movements frequently appeared to overlap. Amplitude, velocity, and acceleration of microstimulation-evoked elbow movements were assessed quantitatively. With increasing stimulus current, each of these parameters increased monotonically until saturation occurred. The spread of intrastriatal microstimulation currents was found to be comparable to that reported for motor cortex. The effective radius of 40-microA putamen microstimulation currents was estimated to be approximately 150 micron. This effectively rules out the possibility of current spread to the internal capsule. Microstimulation effects were abolished by fiber-sparing lesions produced by microinjections of the neurotoxin ibotenic acid. Moreover, chronaxie measurements in putamen (327 +/- 47 microseconds) were significantly higher than for capsular stimulation (150 +/- 32 microseconds). These observations are consistent with the proposal that movements evoked by putamen microstimulation resulted from activation of putamen output neurons. On the other hand, a possible contribution from the antidromic activation of corticostriate afferent terminals or axons cannot be excluded.

Spinothalamic and spinohypothalamic tract neurons in the sacral spinal cord of rats. I. Locations of antidromically identified axons in the cervical cord and diencephalon

1996 ◽  
Vol 75 (6) ◽  
pp. 2581-2605 ◽  
Author(s):  
J. T. Katter ◽  
R. J. Dado ◽  
E. Kostarczyk ◽  
G. J. Giesler
Keyword(s):  
Dorsal Horn ◽  
Dynamic Range ◽  
Optic Tract ◽  
Zona Incerta ◽  
Cervical Cord ◽  
Medial Lemniscus ◽  
Spinothalamic Tract ◽  
Antidromic Activation ◽  
Medial Geniculate ◽  
Spinal Segments

1. A goal of this study was to determine the sites in the diencephalon to which neurons in sacral spinal segments of rats project. Therefore, 95 neurons were recorded extracellularly in spinal segments L6-S2 of rats that were anesthetized with urethan. These neurons were activated initially antidromically with currents < or = 30 microA from a monopolar stimulating electrode placed into the contralateral posterior diencephalon. The mean +/- SE current for antidromic activation from these sites was 16 +/- 0.8 microA. These neurons were recorded in the superficial dorsal horn (4%), deep dorsal horn (89%), and intermediate zone and ventral horn (4%). 2. Systematic antidromic mapping techniques were used to map the axonal projections of 41 of these neurons within the diencephalon. Thirty-three neurons (80%) could be activated antidromically with currents < or = 30 microA only from points in the contralateral thalamus and are referred to as spinothalamic tract (STT) neurons. Eight neurons (20%) were activated antidromically with low currents from points in both the contralateral thalamus and hypothalamus, and these neurons are referred to as spinothalamic tract/ spinohypothalamic tract (STT/SHT) neurons. Three additional neurons were activated antidromically with currents < or = 30 microA only from points within the contralateral hypothalamus and are referred to as spinohypothalamic tract (SHT) neurons. The diencephalic projections of another 51 neurons were mapped incompletely. These neurons are referred to as spinothalamic/unknown (STT/ U) neurons to indicate that it was not known whether their axons ascended beyond the site in the thalamus from which they initially were activated antidromically. 3. For 31 STT neurons, the most anterior point at which antidromic activation was achieved with currents < or = 30 microA was determined. Fourteen (45%) were activated antidromically only from sites posterior to the ventrobasal complex (VbC) of the thalamus. Sixteen STT neurons (52%) were activated antidromically with low currents from sites at the level of the VbC, but not from more anterior levels. One STT neuron (3%) was activated antidromically from the anteroventral nucleus of the thalamus. 4. STT/SHT neurons were antidromically activated with currents < or = 30 microA from the medial lemniscus (ML), anterior pretectal nucleus (APt), posterior nuclear group and medial geniculate nucleus (Po/MG), and zona incerta in the thalamus and from the optic tract (OT), supraoptic decussation, or lateral area of the hypothalamus. No differences in the sites in the thalamus from which STT and STT/SHT neurons were activated antidromically were apparent. Five STT/SHT neurons (62%) were activated antidromically from points in the thalamus in the posterior diencephalon and from points in the hypothalamus at more anterior levels. Three STT/SHT neurons (38%) were activated antidromically with currents < or = 30 microA from sites in both the thalamus and hypothalamus at the same anterior-posterior level of the diencephalon. All three of these STT/SHT neurons projected to the intralaminar nuclei (parafascicular or central lateral nuclei) of the thalamus. 5. Seven STT/SHT neurons were tested for additional projections to the ipsilateral brain. Two (29%) were activated antidromically with currents < or = 30 microA and at longer latencies from sites in the ipsilateral diencephalon. One could only be activated antidromically from the hypothalamus ipsilaterally. The other was activated antidromically at progressively increasing latencies from points in the ipsilateral brain that extended as far posteriorly as the posterior pole of the MG. 6. Fifty-eight STT, STT/SHT, and STT/U neurons were classified as low-threshold (LT), wide dynamic range (WDR), or highthreshold (HT) neurons based on their responsiveness to innocuous and noxious mechanical stimuli applied to their cutaneous receptive fields.(ABSTRACT TRUNCATED)

Chemical activation of C1–C2 spinal neurons modulates activity of thoracic respiratory interneurons in rats

2002 ◽  
Vol 283 (4) ◽  
pp. R843-R852 ◽  
Author(s):  
C. Qin ◽  
J. P. Farber ◽  
M. J. Chandler ◽  
R. D. Foreman
Keyword(s):  
Dorsal Horn ◽  
Chemical Activation ◽  
Dorsal Surface ◽  
Spinal Neurons ◽  
Nerve Activity ◽  
Dorsal Horn Neurons ◽  
Upper Cervical ◽  
Spinal Segments ◽  
Discharge Patterns ◽  
Antidromic Response

Discharge patterns of thoracic dorsal horn neurons are influenced by chemical activation of cell bodies in cervical spinal segments C1–C2. The present aim was to examine whether such activation would specifically affect thoracic respiratory interneurons (TRINs) of the deep dorsal horn and intermediate zone in pentobarbital sodium-anesthetized, paralyzed, artificially ventilated rats. We also characterized discharge patterns and pathways of TRIN activation in rats. A total of 77 cells were classified as TRINs by location, continued burst activity related to phrenic discharge when the respirator was stopped, and lack of antidromic response from selected pathways. A variety of respiration-phased discharge patterns was documented whose pathways were interrupted by ipsilateral C1 transection. Glutamate pledgets (1 M, 1 min) on the dorsal surface of the spinal cord inhibited 22/49, excited 15/49, or excited/inhibited 3/49 tested cells. Incidence of responses did not depend on whether the phase of TRIN discharge was inspiratory, expiratory, or biphasic. Phrenic nerve activity was unaffected by chemical activation of C1–C2 in this preparation. Besides supraspinal input, TRIN activity may be influenced by upper cervical modulatory pathways.

Dopaminergic modulation of glutamate-induced excitations of neurons in the neostriatum and nucleus accumbens of awake, unrestrained rats

1996 ◽  
Vol 75 (1) ◽  
pp. 142-153 ◽  
Author(s):  
E. A. Kiyatkin ◽  
G. V. Rebec
Keyword(s):  
Nucleus Accumbens ◽  
Impulse Activity ◽  
Initial Response ◽  
Inhibitory Effect ◽  
Unit Recording ◽  
Basal Activity ◽  
Irregular Pattern ◽  
Modal Values ◽  
Induced Changes ◽  
Goal Directed Behavior

1. Single-unit recording and iontophoresis were used in awake, unrestrained rats to assess the action of dopamine (DA) and glutamate (GLU) on the spontaneous activity of neurons in the neostriatum and nucleus accumbens. 2. A total of 88 neurons (40 neostriatal and 48 accumbal) was recorded from 7 rats during 13 recording sessions. During quiet rest, spontaneously active neurons discharged at a slow rate and irregular pattern of activity. Accumbal neurons had a significantly faster level of basal activity than neostriatal neurons (modal values of 10.3 vs. 2.1 imp/s, respectively). 3. Neuronal responses to separate applications of DA and GLU (5-80 nA; 15-30 s) were tested on 40 and 76 units (195 and 227 applications), respectively, during the quiet resting period. The effect of prolonged DA iontophoresis (5-80 nA; 2-3 min) on GLU-induced changes in impulse activity was tested on 38 units (72 applications). 4. GLU activated all cells in both structures. This response appeared with a latency of 0.5-4.0 s at different ejection currents (5-40 nA; mean threshold of 22.2 nA) and was highly variable (103-11,520% of basal activity). Response magnitude correlated strongly with the rate of basal activity (r = 0.822). 5. DA inhibited 75% of spontaneously active neostriatal and accumbal cells with a mean threshold of 20.4 nA. In contrast to the GLU excitation, the DA-induced inhibition was relatively weak in magnitude (10-90% of basal activity) and occurred with relatively longer on- and offset latencies than GLU (2-20 s). The inhibitory effect of DA was absent during phasic activations of neuronal activity associated with movement. Two neostriatal neurons responded to DA with a dose-dependent excitation. 6. Prolonged DA iontophoresis altered both basal impulse activity (causing a decrease in 36 of 72 applications and an increase in 4) and the magnitude of the GLU-induced activation (decreasing it in 27 of 72 applications and increasing it in 12). The net result was an overall enhancement of the GLU response relative to the DA-induced change in basal activity (74% of cases). This increase in the GLU response occurred at relatively low DA ejection currents (10-30 nA). It was stronger in the nucleus accumbens than in the neostriatum and was most evident on cells having both a moderate level of basal activity and a relatively small initial response to GLU. When DA was ejected at high currents (> 40 nA) and/or the magnitude of the preceding GLU-induced activation was high (> 800% of basal activity), DA tended to decrease the GLU response. 7. DA appears to exert a slight depression of striatal and accumbal activity, which has the effect of amplifying the phasic activation induced by GLU. Because forebrain DA release occurs in response to behaviorally important stimuli, the DA-induced modulation of the GLU response may play an important role in regulating goal-directed behavior.

Properties and tectal projections of monkey retinal ganglion cells

1977 ◽  
Vol 40 (6) ◽  
pp. 1443-1443 ◽  
Author(s):  
Peter H. Schiller ◽  
Joseph G. Malpeli
Keyword(s):  
Single Cell ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Retinal Ganglion ◽  
Antidromic Activation ◽  
Time Marker ◽  
Antidromic Response

Page 432: Peter H. Schiller and Joseph G. Malpeli, “Properties and tectal projections of monkey retinal ganglion cells.” The legend to the figure at the bottom of page 432 should read: fig. 3. A: orthodromic potential of single cell in retina. B: antidromic response of same cell. Two components of the response evident which show considerable variation with antidromic activation. The second component is absent in the fifth trace. Time marker represents 1 ms.

Functional differentiation of human brain progenitor cells

2006 ◽  
Vol 2 (3) ◽  
pp. 187-198
Author(s):  
CONRAD A. MESSAM ◽  
SHINGHUA DING ◽  
PHILIP G. HAYDON
Keyword(s):  
Human Brain ◽  
Progenitor Cells ◽  
Functional Properties ◽  
Ampa Receptors ◽  
Glutamate Transporter ◽  
Functional Differentiation ◽  
Small Population ◽  
Physiological Properties ◽  
Current Voltage ◽  
Neuronal Proteins

Stem cells and progenitor cells derived from the developing human brain have been shown to differentiate into neurons and astrocytes. However, few studies have examined the functional, physiological properties of these differentiated neurons and astrocytes. In this study we have used immunocytochemistry in combination with electrophysiology to examine protein machinery and functional properties of neurons and astrocytes differentiated from human brain progenitor cells (hBPCs). Our results show that serum induces mainly astrocytic phenotype cells that express GFAP and have physiological properties that are typical of astrocytes. hBPCs differentiated with BDNF and PDGF develop mainly into neurons expressing mature neuronal proteins MAP-2, synaptobrevin II and vesicular glutamate transporter I in the process, plus a small population of GFAP-positive radial cells. Based on electrophysiology of BDNF/PDGF-treated cells two classes of cell were identified. Class I cells have functional neuronal properties, including functional voltage-gated Na+ and K+ currents, functional AMPA receptors and the ability to generate action potentials. A smaller subpopulation of cells (Class II cells) expresses GFAP and exhibit functional properties of astrocytes, including linear current–voltage relationship and dye-coupling.

Adrenal versus nonadrenal sympathetic preganglionic neurones in the lower thoracic intermediolateral nucleus of the cat: effects of serotonin, substance P, and thyrotropin-releasing hormone

1990 ◽  
Vol 68 (8) ◽  
pp. 1108-1118 ◽  
Author(s):  
S. B. Backman ◽  
H. Sequeira-Martinho ◽  
J. L. Henry
Keyword(s):  
Substance P ◽  
Gradual Increase ◽  
Thyrotropin Releasing Hormone ◽  
Releasing Hormone ◽  
Iontophoretic Application ◽  
Preganglionic Neurone ◽  
Spinal Segments ◽  
Excitatory Responses ◽  
Intermediolateral Nucleus ◽  
Chemical Mediators

Adrenal and nonadrenal sympathetic preganglionic neurones (SPNs) in the intermediolateral nucleus of spinal segments T8–T10 in the cat were compared according to their responses to iontophoretic application of serotonin, substance P, and thyrotropin-releasing hormone (TRH). Responses of both types of SPN to iontophoretic application of serotonin were characterized by an increase in the rate of discharge that was slow in onset (mean ± SD = 36 ± 21 s) and prolonged in afterdischarge (115 ± 70 s) following termination of application. Depression was never observed and responses were similar whether using serotonin at a pH of 3.3 or 4.5, suggesting that the absence of a depressant effect cannot be accounted for by pH, as has been reported with cortical neurones. Iontophoretic application of methysergide resulted in a decrease in the rate of discharge of both types of SPN and blocked the excitatory responses to serotonin. Adrenal and nonadrenal SPNs were excited by iontophoretic application of substance P. Responses of both types of SPN were similar and were characterized by a gradual increase in the rate of discharge that was slow in onset (42 ± 27 s) and prolonged in afterdischarge (96 ± 42 s). Finally, adrenal and nonadrenal SPNs were also weakly excited by iontophoretic application of TRH. These responses were slow in onset (48 ± 27 s) and prolonged in afterdischarge (78 ± 35 s). These data indicate that serotonin, substance P, and TRH exert excitatory effects on functionally dissimilar sympathetic preganglionic neurones and support the possibility that they may be chemical mediators of synaptic transmission in the intermediolaterai nucleus. In addition, these data may be interpreted to support the notion that serotonin, substance P, and TRH are involved in global activation of the sympathetic nervous system.Key words: sympathetic preganglionic neurone, spinal cord, lateral horn, iontophoresis, serotonin, substance P, thyrotropin-releasing hormone.

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