Gastric vagal-evoked and greater splanchnic-evoked unitary responses in the hypothalamus

1993 ◽  
Vol 264 (6) ◽  
pp. G1133-G1141 ◽  
Author(s):  
W. D. Barber ◽  
C. S. Yuan
Keyword(s):  
Action Potentials ◽  
Time Course ◽  
Splanchnic Nerve ◽  
Nerve Fibers ◽  
Hypothalamic Neurons ◽  
Proximal Stomach ◽  
Neuronal Interactions ◽  
Greater Splanchnic Nerve ◽  
Two Peaks ◽  
Stimulation Of

Gastric vagal and greater splanchnic nerve fibers were electrically stimulated to localize and characterize neuronal interactions in the hypothalamus of anesthetized cats. Extracellular recordings from 635 hypothalamic units were identified that responded to electrical stimulation of the left greater splanchnic nerve or gastric vagal fibers serving the proximal stomach. A total of 504 hypothalamic units in this group received input from both gastric vagal and greater splanchnic nerves. The gastric vagal-evoked hypothalamic (GVeH) and greater splanchnic-evoked hypothalamic (SeH) responses were widely distributed in the medial, paraventricular, and dorsomedial nuclei and lateral hypothalamus. The conduction velocity of the SeH response was significantly greater than the GVeH response. The latency of the SeH response showed two peaks [58 +/- 15.7 (SD) ms and 136 +/- 18.3 (SD) ms] indicating that the splanchnic input terminated on two different groups or populations of hypothalamic neurons. It also suggested that different pathways or fiber diameters in the pathway may be involved in the transmission of splanchnic input to the hypothalamus. The majority of the GVeH and SeH unitary responses were multiple spikes or short trains of action potentials. Excitatory and inhibitory responses were observed in tonically active hypothalamic units that responded to gastric vagal or greater splanchnic input. The duration of decreased excitability to gastric vagal or greater splanchnic input was significantly greater than the period of increased excitability. The condition-test paradigm was used to determine the time course of convergent gastric vagal-greater splanchnic input on single hypothalamic neurons.(ABSTRACT TRUNCATED AT 250 WORDS)

Time course of renal responses to greater splanchnic nerve stimulation

1991 ◽  
Vol 260 (5) ◽  
pp. R894-R905 ◽  
Author(s):  
B. N. Van Vliet ◽  
M. J. Smith ◽  
A. C. Guyton
Keyword(s):  
Time Course ◽  
Plasma Renin ◽  
Splanchnic Nerve ◽  
Sympathetic Stimulation ◽  
Renal Vasculature ◽  
Acute Response ◽  
Anesthetized Dogs ◽  
Time Courses ◽  
Greater Splanchnic Nerve ◽  
Renal Responses

The objective of the present study was to describe the time courses of renal responses during renal sympathetic stimulation and to determine whether the kidney can provide a sustained response to sympathetic stimulation for 3 h. In four pentobarbital sodium-anesthetized dogs, stimulation (3.3 Hz) of a greater splanchnic nerve (GSN) on one side caused reductions in renal blood flow (RBF) and sodium excretion (UNaV) of both stimulated and contralateral-denervated kidneys, plus an increase in plasma renin activity (PRA). During continued stimulation, RBF partially recovered, but UNaV fell to less than 5% of control and PRA rose and remained at least eight times above control. In nine dogs, a single GSN was stimulated after ipsilateral adrenal medullectomy and ligation of the splanchnic circulation. The acute response to GSN stimulation was now confined to the ipsilateral kidney. Ipsilateral RBF fell by 32 +/- 10% but returned to 85 +/- 5% of control values by the end of the stimulation period. Contralateral RBF fell slowly by approximately 10%. Ipsilateral and contralateral UNaV fell to 34 +/- 10 and 43 +/- 11% of control values, respectively. PRA increased rapidly at the onset of GSN stimulation and remained at least 2.8 times control levels. After stimulation, RBF, UNaV, and PRA returned toward control levels. These results confirm the findings of others that the response of the renal vasculature to sympathetic stimulation is mainly transient. However, they additionally demonstrate a strong and sustained decrease in UNaV lasting for the total 3-h period of sympathetic stimulation.

Mechanism of stimulation of duodenal contractions by the greater splanchnic nerve

1987 ◽  
Vol 104 (3) ◽  
pp. 1186-1189
Author(s):  
V. M. Smirnov ◽  
V. A. Klevtsov ◽  
N. A. Smirnova ◽  
A. �. Lychkova
Keyword(s):  
Splanchnic Nerve ◽  
Greater Splanchnic Nerve ◽  
Stimulation Of

Neurogenic hyperalgesia: psychophysical studies of underlying mechanisms

1991 ◽  
Vol 66 (1) ◽  
pp. 190-211 ◽  
Author(s):  
R. H. LaMotte ◽  
C. N. Shain ◽  
D. A. Simone ◽  
E. F. Tsai
Keyword(s):  
Injection Site ◽  
Neural Activity ◽  
Time Course ◽  
Normal Skin ◽  
Nerve Fibers ◽  
Intradermal Injection ◽  
Mechanical Hyperalgesia ◽  
Underlying Mechanisms ◽  
Psychophysical Studies ◽  
Stimulation Of

1. Psychophysical studies were made, in humans, of the sensory characteristics and underlying mechanisms of the hyperalgesia (often termed “secondary hyperalgesia”) that occurs in uninjured skin surrounding a local cutaneous injury. The hyperalgesia was characterized by lowered pain thresholds and enhanced magnitude of pain to normally painful stimuli. The “injury” was produced by a single intradermal injection of 10 microliters of 100 micrograms of capsaicin, the algesic substance in hot chili peppers. 2. On injection of capsaicin into the volar forearm, the subjects experienced intense burning pain, accompanied immediately by the formation of three areas of hyperalgesia surrounding the injection site. The largest mean area (55 cm2) was hyperalgesic to a normally painful punctate stimulation of the skin. Nested within this was an area of tenderness to gentle stroking (38 cm2) and a much smaller area of hyperalgesia to heat (2 cm2). An area of analgesia to pinprick, approximately 4 mm in diameter and centered on the injection site, developed within minutes and typically disappeared within 24 h. The hyperalgesia to heat and to stroking disappeared within 1-2 h, whereas the hyperalgesia to punctate stimuli, although gradually decreasing in area, lasted from 13 to 24 h. 3. The radial spread of the mechanical hyperalgesia (to punctate and stroking stimuli) away from the injury was dependent on neural activity and not produced, for example, by algesic substances transported away from the injury. The injection of capsaicin into a small area of anesthetized skin did not produce hyperalgesia in the surrounding, unanesthetized skin. Also, the hyperalgesia in normal skin readily crossed a tight arm band that blocked the circulation of blood and lymph. 4. The spread of mechanical hyperalgesia away from the injury was peripherally mediated via cutaneous nerve fibers because it was blocked by a thin mediolateral strip of cutaneous anesthesia placed 1 cm away from the capsaicin injection site. Hyperalgesia developed normally on the capsaicin side of the strip but not on the other side. 5. Heat stimulation of the skin that produced pain that was equivalent in magnitude and time course to that produced by an injection of capsaicin (10 micrograms) resulted in much smaller areas of mechanical hyperalgesia. It was postulated that there exist special chemosensitive primary afferent nerve fibers that are more effective in producing mechanical hyperalgesia than are the known thermo- and mechanosensitive nociceptive nerve fibers. 6. Once developed, the mechanical hyperalgesia became only partially dependent on peripheral neural activity originating at the site of injury.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Stimulation of 3-hydroxy-3-methylglutaryl-coenzyme A reductase in mouse uterine epithelial cells by oestradiol-17 β

1984 ◽  
Vol 218 (3) ◽  
pp. 849-855 ◽  
Author(s):  
P A Wilce ◽  
L Leijten ◽  
L Martin
Keyword(s):  
Cell Cycle ◽  
Enzyme Activity ◽  
Epithelial Cells ◽  
Time Course ◽  
Hormone Treatment ◽  
S Phase ◽  
Uterine Epithelial Cells ◽  
Coa Reductase ◽  
Two Peaks ◽  
Stimulation Of

The characteristics of 3-hydroxy-3-methylglutaryl-CoA reductase from mouse uterine epithelial cells were studied. Preliminary experiments showed that enzyme activity was stimulated approx. 10-fold 18h after administration of 100ng of oestradiol-17 beta. This activity was associated with all particulate fractions of the uterine luminal cell. The Km for D-3-hydroxy-3-methylglutaryl-CoA was 5.54 +/- 1.12 microM. The detailed time-course of oestrogen stimulation showed two peaks of activity, 9 and 15h after hormone treatment. The DNA content of the epithelial cells doubled between 6 and 12h after hormone treatment, whereas the protein content increased linearly over the 18h period. The peak of enzyme activity at 9h is associated with early S phase of the epithelial cells; the peak at 15h may be associated with a second S phase or with mitosis. Pretreatment with progesterone for 3 days before injection of oestradiol-17 beta (a treatment which inhibits uterine epithelial DNA synthesis) reduced the oestrogenic stimulation of enzyme activity by 63%; progesterone treatment alone did not stimulate enzyme activity. These data suggest that uterine epithelial 3-hydroxy-3-methylglutaryl-CoA reductase may play an important role in the cell cycle in this tissue.

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.

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.

Electrophysiological study on nervous pathway from splanchnic nerve to vagus nerve in rat

1983 ◽  
Vol 244 (6) ◽  
pp. R888-R890 ◽  
Author(s):  
A. Niijima
Keyword(s):  
Vagus Nerve ◽  
Action Potentials ◽  
Electrophysiological Study ◽  
Splanchnic Nerve ◽  
Hepatic Branch ◽  
Stimulation Of

Action potentials evoked by the stimulation of the hepatic branch of the splanchnic nerve were recorded from the peripheral cut end of the dorsal celiac branch of the vagus nerve in the rat. Action potentials were clearly demonstrated after averaging over 100 times by a computer. The observations indicate the existence of a nervous pathway from the hepatic branch of the splanchnic nerve to the dorsal celiac branch of the vagus nerve in the rat.

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