Pre- and postganglionic sympathetic activity in splanchnic nerves of rats

1981 ◽  
Vol 241 (1) ◽  
pp. R55-R61 ◽  
Author(s):  
B. G. Celler ◽  
L. P. Schramm
Keyword(s):  
Electrical Stimulation ◽  
Sympathetic Activity ◽  
Wistar Rats ◽  
Splanchnic Nerve ◽  
Ganglionic Blockade ◽  
Splanchnic Nerves ◽  
Before And After ◽  
Evoked Activity ◽  
Greater Splanchnic Nerve ◽  
Stimulation Of

Integrated sympathetic activity was recorded on anterior or posterior divisions of the greater splanchnic nerve (GSN) in anesthetized, acutely spinalized, artificially respired Wistar rats before and after ganglionic blockade by hexamethonium. Focal electrical stimulation of spinal sympathoexcitatory pathways elicited large increases in splanchnic sympathetic activity. Ganglionic blockade showed that the anterior and posterior divisions of the GSN are predominantly preganglionic and postganglionic, respectively. Histological examination of excised splanchnic nerves and sympathetic chains indicated that splanchnic postganglionic cell bodies must lie in the chain ganglia rather than within the GSN. Postganglionic responses were calculated for each rat by subtracting responses recorded after ganglionic blockade from responses recorded before ganglionic blockade. As expected, postganglionic responses exhibited longer onset latencies than preganglionic responses. However, evoked activity increased and decreased more rapidly in postganglionic fibers than in preganglionic fibers. Responses to stimulus trains were also better maintained in postganglionic than in preganglionic fibers.

Diminished sympathetic silent period in spontaneously hypertensive rats

1979 ◽  
Vol 236 (3) ◽  
pp. R147-R152 ◽  
Author(s):  
L. P. Schramm ◽  
G. N. Barton
Keyword(s):  
Electrical Stimulation ◽  
Sympathetic Activity ◽  
Spontaneously Hypertensive Rats ◽  
Silent Period ◽  
Spontaneous Hypertension ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Splanchnic Nerves ◽  
Wistar Kyoto ◽  
Stimulation Of

To determine if elevated sympathetic activity occurs in spontaneously hypertension, the silent period induced in splanchnic nerves following electrical stimulation of dorsal medullary sympathoexcitatory sites was compared in anesthetized normotensive Wistar Kyoto rats (WKYs) and Okamoto spontaneously hypertensive rats (SHRs). The strength of silent periods was defined as the degree of inhibition of responses to testing stimuli delivered at various latencies following conditioning trains, and it was assumed to be inversely related to the level of sympathetic activity. Weanling SHRs exhibited weaker silent periods than weanling WKYs although, at that age, the arterial pressures of the strains were not significantly different. Silent periods were also weaker in adult SHRs than in adult WKYs. This difference persisted after arterial pressures, which fell under anesthesia, were raised by phenylephrine infusions to the respective "normal" levels in each strain. These results support the hypothesis that elevated sympathetic activity exists during both the development and maintenance of spontaneous hypertension in rats.

Splanchnic and somatic afferent convergence on cervical spinal neurons of the rat

1994 ◽  
Vol 266 (1) ◽  
pp. R268-R276 ◽  
Author(s):  
E. W. Akeyson ◽  
L. P. Schramm
Keyword(s):  
Electrical Stimulation ◽  
Cervical Spinal Cord ◽  
Receptive Fields ◽  
Splanchnic Nerve ◽  
Whole Body ◽  
Spinal Neurons ◽  
Somatic Afferents ◽  
Greater Splanchnic Nerve ◽  
Somatic Input ◽  
Stimulation Of

The rostral cervical spinal cord is increasingly being considered the source of important propriospinal regulation. To better understand the substrate for this function, we investigated the effects of stimulation of the greater splanchnic nerve (GSN) and both thoracic and cervical somatic afferents on the activity of cervical spinal neurons. Extracellular single-neuron recordings were made in the C2-C5 spinal segments of chloralose-anesthetized, paralyzed, and artificially ventilated rats. Neurons were classified according to their responses to GSN stimulation. Neurons were inhibited by this stimulation as frequently as they were excited. We then studied the characteristics of cervical and thoracic convergent somatic input to each class of neurons. Although all cervical neurons that responded to GSN stimulation responded to electrical stimulation of the iliohypogastric nerve (IHN), only the few neurons that exhibited whole body receptive fields (RF) responded to natural thoracic somatic stimuli. Responses to electrical stimulation of the GSN and IHN were similar for most neurons; most exhibited nociceptive cutaneous RFs in cervical dermatomes. These data indicate that input from cervical somatic afferents and from both thoracic visceral and thoracic somatic afferents converge on individual splanchnic-receptive cervical neurons. Although these neurons exhibited the predicted cervical somatic RFs, responses from thoracic levels did not exhibit discrete RFs, requiring instead more synchronous or more spatially convergent input.

Role of baroreceptor afferents on area postrema-induced inhibition of sympathetic activity

1991 ◽  
Vol 260 (4) ◽  
pp. H1353-H1358
Author(s):  
M. Hay ◽  
E. M. Hasser ◽  
K. P. Undesser ◽  
V. S. Bishop
Keyword(s):  
Electrical Stimulation ◽  
Sympathetic Activity ◽  
Area Postrema ◽  
Afferent Input ◽  
Dependent Manner ◽  
Chemical Application ◽  
Renal Sympathetic Nerve Activity ◽  
Before And After ◽  
Stimulation Of

Activation of the area postrema by either electrical stimulation or chemical application of L-glutamate has been shown to result in an enhancement of cardiovascular baroreflexes similar to that seen with systemic infusions of arginine vasopressin (AVP). In addition, it has been found that the effects of AVP on baroreflex inhibition of renal sympathetic nerve activity (RSNA) are similar to those observed with phenylephrine following lesions of the area postrema or after partial denervation of baroreceptor afferents. The present study was undertaken to determine the role of baroreceptor afferent input on area postrema stimulation-induced decreases in sympathetic activity. In anesthetized rabbits, the responses of arterial pressure, heart rate, and RSNA to area postrema electrical stimulation were obtained before and after progressive sinoaortic denervation and vagotomy. Stimulation of the area postrema in carotid sinus-denervated animals consistently decreased RSNA in a frequency-dependent manner. However, following bilateral removal of both the aortic nerves and the vagi, electrical stimulation of the area postrema had no effect on RSNA. These results suggest that the ability of area postrema stimulation to inhibit RSNA is dependent on the presence of baroreceptor afferent input.

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.

Control of bilateral seminal emissions from ejaculatory ducts by a lumbar splanchnic nerve

1993 ◽  
Vol 265 (4) ◽  
pp. R743-R748 ◽  
Author(s):  
K. Kihara ◽  
K. Sato ◽  
M. Ando ◽  
T. Morita ◽  
H. Oshima
Keyword(s):  
Electrical Stimulation ◽  
Splanchnic Nerve ◽  
Contralateral Side ◽  
The Other ◽  
Hypogastric Nerve ◽  
Splanchnic Nerves ◽  
Posterior Urethra ◽  
Stimulation Of

To investigate the route of efferent signals for seminal emissions from ejaculatory ducts (SEEDs), canine lumbar splanchnic nerves (LSNs) were electrically stimulated. SEED was confirmed by visual verification of seminal flow into the exposed posterior urethra. In intact dogs, electrical stimulation of an LSN caused bilateral SEEDs in 13 of 16 dogs examined, with a greater volume at the stimulated side. After transection of a unilateral hypogastric nerve, bilateral SEEDs occurred by electrical stimulation of the contralateral LSN in 11 of 14 dogs with a greater volume at the stimulated side and by the stimulation of the ipsilateral LSN in 13 of 15 dogs with a greater volume at the contralateral side. Contraction pressure of the epididymal tail under the same conditions harmonized with the above results. We conclude that each LSN generates bilateral SEEDs by sending signals to bilateral epididymal tails and that some of the signals through each LSN cross to the other side at the caudal mesenteric plexus and/or the prostatic plexus.

Greater splanchnic excitation of primate T1-T5 spinothalamic neurons

1984 ◽  
Vol 51 (3) ◽  
pp. 592-603 ◽  
Author(s):  
W. S. Ammons ◽  
R. W. Blair ◽  
R. D. Foreman
Keyword(s):  
Electrical Stimulation ◽  
Cell Activation ◽  
Receptive Fields ◽  
Splanchnic Nerve ◽  
Inhibitory Effect ◽  
Sympathetic Stimulation ◽  
Bilateral Vagotomy ◽  
Somatic Receptive Fields ◽  
Greater Splanchnic Nerve ◽  
Stimulation Of

Effects of electrical stimulation of the left greater splanchnic nerve (SPL) on T1-T5 spinothalamic (STT) neurons were determined. Eighty-five STT neurons were studied in 36 anesthetized monkeys (Macaca fascicularis). All neurons were excited by manipulation of their somatic receptive fields and by electrical stimulation of cardiopulmonary (CP) sympathetic afferent fibers. SPL stimulation excited 63 (74%) STT neurons. There was an increasing percentage of cells with SPL input at more caudal segments and in deeper laminae. Both SPL and CP sympathetic stimulation elicited early or both early and late responses. Latencies to cell activation were usually shorter for CP sympathetic stimulation than for SPL stimulation (5.4 +/- 0.8 versus 11.3 +/- 2.0 ms for early responses and 44.2 +/- 4.2 versus 111.0 +/- 6.6 ms for late responses). The maximum number of spikes per SPL or CP sympathetic stimulus was determined. In the T2 and T3 segments, early responses to CP sympathetic stimulation were significantly greater. However, at more caudal segments, responses to CP sympathetic input decreased while responses to SPL input increased until at T4 there was no difference in the two responses. In T5, responses to SPL input were greater. No differences in the magnitudes of late responses were observed in any of the segments. The response of six cells to SPL stimulation was inhibited by a train of conditioning stimuli applied to the left thoracic vagus nerve. Maximum inhibition occurred at a CT interval of 50 ms and test responses were significantly reduced at CT intervals as great as 200 ms. Bilateral vagotomy eliminated the inhibitory effect. Cutting the left sympathetic chain between the T5 and T6 rami communicantes eliminated 27% of the response to SPL stimulation. More caudal cuts reduced the response further until 71% of the response was abolished by a cut between T8 and T9. Lesions in the dorsolateral column of the spinal cord had little effect on the responses, while lesions of the lateral and ventrolateral columns reduced or abolished the responses. We conclude that SPL stimulation excites T1-T5 STT neurons by way of extraspinal and intraspinal pathways. SPL information is integrated with information from a variety of other visceral and somatic sources. SPL input to cells with somatic fields in the chest region may explain the clinical phenomenon of chest pain associated with abdominal disorders.

Cross-talk along gastrointestinal tract during electrical stimulation: effects and mechanisms of gastric/colonic stimulation on rectal tone in dogs

2005 ◽  
Vol 288 (6) ◽  
pp. G1195-G1198 ◽  
Author(s):  
Shi Liu ◽  
Lijie Wang ◽  
J. D. Z. Chen
Keyword(s):  
Electrical Stimulation ◽  
Inhibitory Effect ◽  
Adrenergic Blockade ◽  
Rectal Compliance ◽  
Rectal Tone ◽  
Before And After ◽  
Sensory Functions ◽  
Sympathetic Pathway ◽  
Colonic Electrical Stimulation ◽  
Stimulation Of

Gastric electrical stimulation (GES) has been shown to alter motor and sensory functions of the stomach. However, its effects on other organs of the gut have rarely been investigated. The study was performed in 12 dogs implanted with two pairs of electrodes, one on the serosa of the stomach and the other on the colon. The study was composed of two experiments. Experiment 1 was designed to study the effects of GES on rectal tone and compliance in nine dogs compared with colonic electrical stimulation (CES). Rectal tone and compliance were assessed before and after GES or CES. Experiment 2 was performed to study the involvement of sympathetic pathway in 8 of the 12 dogs. The rectal tone was recorded for 30–40 min at baseline and 20 min after intravenous guanethidine. GES or CES was given for 20 min 20 min after the initiation of the infusion. It was found that both GES and CES reduced rectal tone with comparable potency. Rectal compliance was altered neither with GES, nor with CES. The inhibitory effect of GES but not CES on rectal tone was abolished by an adrenergic blockade, guanethidine. GES inhibited rectal tone with a comparable potency with CES but did not alter rectal compliance. The inhibitory effect of GES on rectal tone is mediated by the sympathetic pathway. It should be noted that electrical stimulation of one organ of the gut may have a beneficial or adverse effect on another organ of the gut.

Gastric Secretion Following Vagosplanchnic Nerve Anastomosis

1956 ◽  
Vol 184 (2) ◽  
pp. 418-427 ◽  
Author(s):  
Anthony M. Imparato ◽  
L. Corsan Reid ◽  
J. William Hinton
Keyword(s):  
Electrical Stimulation ◽  
Gastric Secretion ◽  
Functional Relationship ◽  
Early Postoperative Period ◽  
Insulin Hypoglycemia ◽  
Splanchnic Nerves ◽  
Nerve Anastomosis ◽  
Nerve Anastomoses ◽  
Secretory Apparatus ◽  
Stimulation Of

Gastric secretion in response to insulin hypoglycemia and electrical stimulation of the vagus was studied in 18 dogs who had bilateral vagosplanchnic anastomoses in the chest. In six dogs the pattern of gastric secretory response to insulin changed from negative in the early postoperative period to positive between 85 and 613 days postanastomosis. In two, apparent return of vagus function was confirmed by electrical stimulation of the vagi. One of five dogs in whom splanchnovagal nerve anastomoses were performed showed a return of response to insulin at 63 days which was abolished by excision of the anastomoses. On the basis of a review of some of the ideas regarding interpretation of cross nerve anastomoses and some of the conflicting opinions regarding the fiber content of the sympathetic splanchnic nerves, the authors conclude the most likely explanation for the observed phenomena is that there are preganglionic cholinergic fibers in the greater splanchnic nerves whose relationship to the gastric secretory apparatus is similar to that of cholinergic fibers in the vagus. The regenerating fibers of the vagus followed the sheaths of these degenerating fibers and re-established functional relationship with the gastric secretory apparatus.

The release of catecholamines from the adrenal medulla and its modulation by α2-adrenoceptors in the anaesthetized dog

1987 ◽  
Vol 65 (4) ◽  
pp. 550-557 ◽  
Author(s):  
Sylvain Foucart ◽  
Réginald Nadeau ◽  
Jacques de Champlain
Keyword(s):  
Electrical Stimulation ◽  
Adrenal Medulla ◽  
Plasma Concentrations ◽  
Splanchnic Nerve ◽  
Feedback Mechanism ◽  
Adrenal Vein ◽  
Low Frequencies ◽  
Negative Feedback Mechanism ◽  
Frequency Of Stimulation ◽  
Stimulation Of

The adrenal nerve of anaesthetized and vagotomized dogs was electrically stimulated (10 V pulses of 2 ms duration for 10 min) at frequencies of 1, 3, 10, and 25 Hz. There was a correlation between the frequency of stimulation and the plasma concentrations of epinephrine, norepinephrine, and dopamine in the adrenal vein, mainly after the 1st min of stimulation and the maximal concentration was reached sooner with higher frequencies of stimulation. Moreover, the relative percentage of catecholamines released in response to the electrical stimulation was not changed by the frequency of stimulation. To test the hypothesis that a local negative feedback mechanism mediated by α2-adrenoceptors exists in the adrenal medulla, the effects of the systemic administration of clonidine (α2-agonist) and yohimbine (α2-antagonist) on the concentrations of catecholamines in the adrenal vein were evaluated during the electrical stimulation of the adrenal nerve (5 V pulses of 2 ms duration for 3 min) at 3 Hz. Moreover, the effects of the systemic injections of more specific α2-agonist and antagonist (oxymetazoline and idazoxan) were tested on the release of catecholamines in the adrenal vein in response to electrical stimulation of the splanchnic nerve at 1 and 3 Hz frequencies. The injection of 0.5 mg/kg of yohimbine caused a significant increase in the concentrations of epinephrine and norepinephrine in the adrenal vein induced by the electrical stimulation of the adrenal nerve and the injection of 15 μg/kg of clonidine had no effects. In the second series of experiments, the injection of 2 μg/kg of oxymetazoline caused a significant decrease in the release of epinephrine and norepinephrine at 1 Hz, but similarly to clonidine, there were no changes at 3 Hz. In contrast, the release of epinephrine and dopamine in response to electrical stimulation of the splanchnic nerve was increased at 3 Hz after the injection of idazoxan, but not at 1 Hz. It is concluded that the adrenal medulla catecholamines secretion appears to be partly modulated by a presynaptic inhibitory mechanism that involves α2-adrenoceptors. The observation that agonists appear to be more efficient at low frequencies of stimulation while antagonists appear to be more efficient at higher frequencies could be explained by the possibility that adrenal medullary α2-receptors would be saturated at higher frequencies of stimulation.

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