Effects of sympathetic nerve stimulation on membrane potential in the circular muscle layer of mouse distal colon

1998 ◽  
Vol 10 (6) ◽  
pp. 543-552 ◽  
Author(s):  
SPENCER ◽  
BYWATER ◽  
KLEMM
Keyword(s):  
Membrane Potential ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Circular Muscle ◽  
Distal Colon ◽  
Muscle Layer ◽  
Sympathetic Nerve Stimulation ◽  
Circular Muscle Layer

Responses of muscles of cat small intestine to autonomic nerve stimulation

1963 ◽  
Vol 204 (2) ◽  
pp. 352-358 ◽  
Author(s):  
Gordon L. Van Harn
Keyword(s):  
Small Intestine ◽  
Muscle Contraction ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Intraluminal Pressure ◽  
Sympathetic Nerve Stimulation ◽  
Longitudinal Muscle Layer

The externally recorded slow waves from the cat small intestine originate in the longitudinal muscle layer. In vitro the slow waves are recorded from all layers of the intestine if the segment is not immersed in a saline bath. When the longitudinal layer is removed from one region, the magnitude of the slow-wave potential in the other intestinal layers decreases as the distance from the intact longitudinal muscle layer is increased. An active intestine, in vivo, responds to sympathetic nerve stimulation by a hyperpolarization, cessation of spikes, and inhibition of muscle contraction. During inactivity of the intestine, either vagus or sympathetic nerve stimulation results in a depolarization, initiation of spikes, and muscle contraction. The nature of the response is influenced by the frequency of nerve stimulation and by the level of activity of the intestinal muscle, which is altered by intraluminal pressure changes. The effect of drugs on the response of the intestine to vagal and sympathetic nerve stimulation is such as to indicate that both inhibitory and excitatory nerve fibers are present in each of the autonomic nerves. The duration of the latent period of the response is long and highly variable, and a response requires 50–100 nerve volleys.

A novel in vitro technique to study extrinsic neural control of rabbit colonic muscle and epithelial function

1993 ◽  
Vol 265 (6) ◽  
pp. G1064-G1070 ◽  
Author(s):  
J. M. Goldhill ◽  
W. H. Percy
Keyword(s):  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Neural Control ◽  
Contractile Activity ◽  
Circular Muscle ◽  
Potential Difference ◽  
Pelvic Nerve ◽  
Sympathetic Nerve Stimulation ◽  
In Vitro Technique

A novel in vitro technique capable of simultaneously measuring distal colonic epithelial potential difference and muscle contraction is described. Under basal conditions, oscillations in both muscle tone and potential difference were observed. Pelvic nerve stimulation was shown to evoke strong "duration" contractile responses in both the longitudinal and circular muscle layers. Additionally, tonic changes in potential difference extending beyond the train of stimuli were observed, suggesting for the first time that colonic ion transport may be influenced by the pelvic nerves. However, it was unclear whether these were direct effects or indirect actions resulting from muscle contractions causing mechanical stimulation of nerves of the submucosal plexus. Lumbar colonic nerve stimulation inhibited spontaneous contractile activity and reduced basal tone in both muscle layers. However, there was no consistent effect of sympathetic nerve stimulation on transepithelial potential difference. Each of the muscle and epithelial effects of sympathetic nerve stimulation was mimicked by exogenous norepinephrine. Based on these data, it is concluded that colonic function is strongly influenced by the extrinsic innervation. Furthermore, relatively long-term modulation of epithelial function can be achieved by short bursts of pelvic nerve activity.

Changes in electrical and mechanical activity during ontogeny of the canine proximal colon

1996 ◽  
Vol 271 (1) ◽  
pp. G184-G191 ◽  
Author(s):  
S. M. Ward
Keyword(s):  
Membrane Potential ◽  
Circular Muscle ◽  
Electrical Field Stimulation ◽  
Muscle Layer ◽  
Proximal Colon ◽  
Mechanical Activity ◽  
Resting Membrane Potential ◽  
Circular Muscle Layer ◽  
Circular Layer ◽  
Spontaneous Contractions

The ontogenetic development of the circular muscle layer of the canine proximal colon was studied in animals from midway through gestation to 30 days old. With age, there was an increase in resting membrane potential along the submucosal surface and a decrease along the myenteric surface of the circular layer. Coinciding with the changes in membrane potential, slow waves increased in amplitude along the submucosal border and decreased in amplitude along the myenteric border. Muscle strips from animals midway through gestation were mechanically quiescent; however, 1 wk before birth spontaneous activity was observed. Electrical field stimulation of enteric nerves increased spontaneous contractions; this increase in activity was reversed to inhibition by atropine. In the presence of atropine and N omega-nitro-L-arginine or N omega-nitro-L-arginine methyl ester, a noncholinergic excitation was revealed at stimulation frequencies > 5 Hz. The results of these studies provide evidence that the canine proximal colon is spontaneously rhythmic and that a functional innervation to the circular muscle layer exists before birth. The gradient in resting membrane potential across the circular layer is absent at birth but develops within 2-3 wk after parturition.

Effects of sympathetic nerve stimulation on membrane potential, [Ca2+]i, and force in the toad sinus venosus

1999 ◽  
Vol 276 (1) ◽  
pp. H115-H128 ◽  
Author(s):  
Narelle J. Bramich ◽  
Helen M. Cousins
Keyword(s):  
Membrane Potential ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Sinus Venosus ◽  
Atpase Inhibitor ◽  
Sympathetic Nerve Stimulation ◽  
Beat Rate ◽  
Intracellular Ca ◽  
Inotropic Responses ◽  
Toad Sinus Venosus

The effects of sympathetic nerve stimulation on beat rate, force, intracellular Ca2+ concentration ([Ca2+]i) measured using fura 2, and membrane potential were recorded from the spontaneously beating toad sinus venosus. Short trains of stimuli evoked an increase in the beat rate and force. During this tachycardia the amplitude of pacemaker action potentials was not changed, but there was an increase in the basal level of [Ca2+]iwith little change in peak [Ca2+]imeasured during each action potential. Depletion of intracellular Ca2+ stores with caffeine (3 mM) abolished all responses to sympathetic nerve stimulation. The effects of caffeine were fully reversible. Caffeine (3 mM), in the presence of the Ca2+-ATPase inhibitor thapsigargin (30 μM), abolished irreversibly the chronotropic and inotropic responses evoked by sympathetic nerve stimulation. Ryanodine (10 μM) attenuated, but did not abolish, these responses. These results suggest that, in the toad sinus venosus, increases in force and beat rate evoked by sympathetic nerve stimulation result from the release of Ca2+ from intracellular Ca2+ stores.

Noncholinergic membrane potential responses to transmural nerve stimulation in the guinea pig ileum

1991 ◽  
Vol 260 (2) ◽  
pp. G240-G249
Author(s):  
J. R. Crist ◽  
X. D. He
Keyword(s):  
Membrane Potential ◽  
Nerve Stimulation ◽  
Circular Muscle ◽  
Longitudinal Axis ◽  
Muscle Layer ◽  
Abrupt Onset ◽  
Neural Pathways ◽  
Neural Input ◽  
Inhibitory Junction Potential ◽  
Junction Potential

We sought to characterize the projections of nonmuscarinic intramural inhibitory and excitatory neural input to the circular muscle layer of the small intestine. Intracellular membrane potential recordings were made in smooth muscle cells from the distal ileum of 22 guinea pigs. Intramural nerve stimulation (4 pulses, 15 mA, 20 Hz, 2 ms) was delivered by two electrodes located at varying distances from the recording electrode along the longitudinal axis of the intestine. The membrane potential responses immediately oral to the stimulus consisted of an abrupt-onset inhibitory junction potential (IJP) followed by two distinct depolarizations, an early excitatory junction potential (EJP) and a late EJP. The early IJP and early and late EJPs were observed as far as 53 +/- 5, 56 +/- 6, and 39 +/- 5 mm oral to the stimulus, respectively. The responses immediately anal to the stimulus consisted of an initial IJP followed by a prolonged hyperpolarization, which was sometimes interrupted by a superimposed EJP. The early IJP, EJP, and late IJP were observed as far as 77 +/- 12, 66 +/- 10, and 37 +/- 13 mm anal to the stimulus, respectively. All excitatory events greater than 5-10 mm oral or anal to the stimulus were blocked by hexamethonium. Hexamethonium slightly antagonized the early IJP oral to the stimulus but had no effect on the early IJP anal to the stimulus. The late IJP was not affected by hexamethonium. These studies are the first to describe a late IJP, which is observed only at sites anal to the stimulus, and a late EJP, which is observed only at sites oral to the stimulus. The neural pathways involved in these late synaptic events (late EJP and IJP) as well as the previously described early synaptic events (early EJP and IJP) are discussed.

Interactive Effects of Verapamil and Sympathetic Nerve Stimulation on the Sinus and AV Nodes in the Canine Hearts.

1992 ◽  
Vol 33 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Katsusuke YANO ◽  
Masanobu HIRATA ◽  
Takao MITSUOKA ◽  
Yoriaki MATSUMOTO ◽  
Tetsuya HIRATA ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Interactive Effects ◽  
Sympathetic Nerve Stimulation

Effects of ouabain on background and voltage-dependent currents in canine colonic myocytes

1990 ◽  
Vol 259 (3) ◽  
pp. C402-C408 ◽  
Author(s):  
E. P. Burke ◽  
K. M. Sanders
Keyword(s):  
Membrane Potential ◽  
Potential Gradient ◽  
Circular Muscle ◽  
Input Resistance ◽  
Pump Current ◽  
Muscle Layer ◽  
Membrane Properties ◽  
Resting Potential ◽  
Voltage Dependent ◽  
In Cells

Previous studies have suggested that the membrane potential gradient across the circular muscle layer of the canine proximal colon is due to a gradient in the contribution of the Na(+)-K(+)-ATPase. Cells at the submucosal border generate approximately 35 mV of pump potential, whereas at the myenteric border the pump contributes very little to resting potential. Results from experiments in intact muscles in which the pump is blocked are somewhat difficult to interpret because of possible effects of pump inhibitors on membrane conductances. Therefore, we studied isolated colonic myocytes to test the effects of ouabain on passive membrane properties and voltage-dependent currents. Ouabain (10(-5) M) depolarized cells and decreased input resistance from 0.487 +/- 0.060 to 0.292 +/- 0.040 G omega. The decrease in resistance was attributed to an increase in K+ conductance. Studies were also performed to measure the ouabain-dependent current. At 37 degrees C, in cells dialyzed with 19 mM intracellular Na+ concentration [( Na+]i), ouabain caused an inward current averaging 71.06 +/- 7.49 pA, which was attributed to blockade of pump current. At 24 degrees C or in cells dialyzed with low [Na+]i (11 mM), ouabain caused little change in holding current. With the input resistance of colonic cells, pump current appears capable of generating at least 35 mV. Thus an electrogenic Na+ pump could contribute significantly to membrane potential.

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