SINGLE PULSE STIMULATION OF GUINEA-PIG VAS DEFERENS AND THE PRESYNAPTIC RECEPTOR HYPOTHESIS

The central pathway mediating a sympatholytic response to stimulation of the superior laryngeal nerve (SLN) was studied in halothane-anesthetized, paralyzed rats. Single-pulse stimulation of SLN inhibited lumbar sympathetic nerve discharge (LSND) with onset latency of 113 +/- 1.7 ms. LSND inhibition was markedly attenuated by bilateral microinjection of kynurenic acid (Kyn, glutamate receptor antagonist, 4.5 nmol/side) into the caudal ventrolateral medulla (CVL) or by bilateral administration of bicuculline methiodide (Bic; gamma-aminobutyric acid-receptor antagonist, 225 pmol/side) into the rostral ventrolateral medulla (RVL). In 13 of 14 cases, the baroreceptor reflex was also severely reduced. Injections of Bic or Kyn elsewhere in the medullary reticular formation were ineffective. Single-pulse stimulation of SLN inhibited 19 of 26 RVL reticulospinal barosensitive cells (onset latency 46 +/- 1.4 ms). This inhibition was attenuated (from 92 +/- 6 to 14 +/- 12%) by iontophoretic application of Bic (n = 7), which also reduced the cells' inhibitory response to aortic coarctation. The remaining seven barosensitive neurons were unaffected by SLN stimulation. In conclusion, the sympathetic baroreflex and the sympathoinhibitory response to SLN stimulation appear to be mediated by similar medullary pathways.

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Respiratory motor responses to cranial nerve afferent stimulation in rats

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1996.271.4.r1054 ◽

1996 ◽

Vol 271 (4) ◽

pp. R1054-R1062 ◽

Cited By ~ 4

Author(s):

F. Hayashi ◽

D. R. McCrimmon

Keyword(s):

Cranial Nerve ◽

Superior Laryngeal Nerve ◽

Single Pulse ◽

Short Latency ◽

Lung Inflation ◽

Dorsal Respiratory Group ◽

Inspiratory Activity ◽

Pharyngeal Branch ◽

Pulse Stimulation ◽

Stimulation Of

It was hypothesized that, because rats appear to lack a prominent disynaptic projection from the dorsal respiratory group to phrenic motoneurons (Phr), they would lack the short-latency excitation of Phr output seen in cats in response to stimulation of some cranial nerve afferents. Single-pulse superior laryngeal nerve (SLN) stimulation elicited a short-latency bilateral excitation of glossopharyngeal (IX) and hypoglossal (XII) nerves and an ipsilateral excitation of pharyngeal branch of vagus (PhX) in 67% of rats, but no excitation of Phr. Vagus (X) stimulation elicited a bilateral excitation of Phr and a predominantly ipsilateral excitation of IX and PhX. Single-pulse stimulation of SLN or X also elicited longer-latency, bilateral decreases in activity of all recorded nerves. Repetitive stimulation (50 Hz) of SLN or X suppressed inspiratory activity and prolonged expiration. Lung inflation (7.5 cmH2O) inhibited Phr and PhX activity; X stimulation inhibited Phr but prolonged PhX activity. In conclusion, rats predictably lack the SLN-induced short latency Phr excitation but exhibit other short latency reflexes for which the underlying circuitry is not clear.

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Synergism between ouabain and monensin in neurogenic responses of guinea-pig vas deferens

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y88-100 ◽

1988 ◽

Vol 66 (5) ◽

pp. 643-647 ◽

Cited By ~ 5

Author(s):

Takeshi Katsuragi ◽

Lulu Kuratomi ◽

Koji Miyamoto ◽

Tatsuo Furukawa

Keyword(s):

Guinea Pig ◽

Time Course ◽

Vas Deferens ◽

Contractile Activity ◽

Atpase Inhibitor ◽

Exchange System ◽

Deficient Medium ◽

Small Contraction ◽

Monensin A ◽

Stimulation Of

Interrelations between ouabain, a Na+–K+ ATPase inhibitor, and monensin, a Na+ ionophore, on noradrenaline liberation and contractile activity were evaluated in the guinea-pig vas deferens. Monensin (1 μM) per se elicited a small contraction of the tissue. However, amplitude and time to the peak of large and sustained contractions evoked by 10 μM ouabain were potentiated and markedly shortened, respectively, by monensin. Contractions elicited by ouabain with or without monensin were prevented by 3 μM phentolamine or by pretreatment with reserpine. Contractions evoked by K+-free solution were augmented by monensin. In an HPLC study, noradrenaline outflow from the vas deferens was moderately and considerably increased by monensin (10 μM) and ouabain (100 μM), respectively. The ouabain-evoked output of noradrenaline was enhanced in the presence of monensin and the time course for maximum noradrenaline release was shortened, as was the contractile activity. This enhanced outflow after ouabain plus monensin was reserpine sensitive but not tetrodotoxin sensitive. Furthermore, this noradrenaline outflow was roughly halved in Na+-deficient medium, but was unaltered in Ca2+-free medium. These findings suggest that the synergistic effect of ouabain and monensin on noradrenaline liberation from the guinea-pig vas deferens may be due to an elevation of cytoplasmic Ca2+ concentrations, presumably resulting from a stimulation of intracellular Na+–Ca2+ exchange system, but not enhanced Ca2+ entry.

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Electrical Pulse Train and Single Pulse Stimulation of the Small Intestine: Acute and Chronic Studies in the Dog

Artificial Organs ◽

10.1111/j.1525-1594.1989.tb02846.x ◽

1989 ◽

Vol 13 (2) ◽

pp. 116-122 ◽

Cited By ~ 8

Author(s):

Anton Moritz ◽

Sharon Grundfest-Broniatowski ◽

Laszlo Ilyes ◽

Jerry Kasick ◽

Gordon Jacobs ◽

...

Keyword(s):

Small Intestine ◽

Pulse Train ◽

Single Pulse ◽

Electrical Pulse ◽

Pulse Stimulation ◽

Stimulation Of

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Disynaptic Inhibition of Omnipause Neurons Following Electrical Stimulation of the Superior Colliculus in Alert Cats

Journal of Neurophysiology ◽

10.1152/jn.2001.85.6.2639 ◽

2001 ◽

Vol 85 (6) ◽

pp. 2639-2642 ◽

Cited By ~ 20

Author(s):

Kaoru Yoshida ◽

Yoshiki Iwamoto ◽

Sohei Chimoto ◽

Hiroshi Shimazu

Keyword(s):

Superior Colliculus ◽

Short Pulse ◽

Single Pulse ◽

Synaptic Organization ◽

Postsynaptic Potentials ◽

Disynaptic Inhibition ◽

Alert Cats ◽

Omnipause Neurons ◽

Pulse Stimulation ◽

Stimulation Of

We investigated the synaptic organization responsible for the inhibition of omnipause neurons (OPNs) following stimulation of the superior colliculus (SC) in alert cats. Stimulation electrodes were implanted bilaterally in the rostral and caudal SC where a short-pulse train induced small and large saccades, respectively. Effects of single-pulse stimulation on OPNs were examined with intracellular and extracellular recordings. In contrast to monosynaptic excitatory postsynaptic potentials, which were induced by rostral SC stimulation, inhibitory postsynaptic potentials were induced with disynaptic latencies (1.3–1.9 ms) from both the rostral and caudal SC in most OPNs. Analysis of a larger extracellular sample complemented intracellular observations. Monosynaptic activation of OPNs was elicited more frequently from rostral sites than from caudal sites, whereas spike suppression with disynaptic latencies was induced by caudal as well as rostral stimulation with similar frequencies. The results imply that disynaptic inhibition is produced by activation of SC cells that are distributed over wide regions related to saccades of different sizes. We suggest that signals from these neurons initiate a saccadic pause of OPNs through single inhibitory interneurons.

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