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.

Transmission of electrical activity through the gastroduodenal junction

1965 ◽  
Vol 208 (3) ◽  
pp. 531-536 ◽  
Author(s):  
Alex Bortoff ◽  
Noah Weg
Keyword(s):  
Small Intestine ◽  
Electrical Activity ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Pyloric Antrum ◽  
Longitudinal Muscle Layer ◽  
Proximal Duodenum ◽  
Electrical And Mechanical Activities ◽  
Electrode Technique

The electrical and mechanical activities of the gastroduodenal junction were studied in isolated cat preparations, using the pressure-electrode technique. The spontaneous electrical activity of the pyloric antrum consists of periodic depolarizations, the configuration of which is somewhat more complex than that of comparable potentials recorded from the longitudinal muscle layer of the small intestine. Like their intestinal counterparts these antral slow waves may be associated with spike potentials which are thought to initiate contractions. The electrical activity at the gastroduodenal junction consists of a combination of antral and duodenal slow waves, sometimes accompanied by spike potentials. In the proximal duodenum, antral slow waves are represented by periodic depolarizations which may be associated with spike potentials followed by contractions. Because of the extension of the antral slow waves into the proximal duodenum, contractions initiated in the antrum may also extend into the proximal duodenum. It is concluded that the gastroduodenal junction is a transition zone, coordinating the electrical and corresponding mechanical activities of the antrum and proximal duodenum.

Separation of enkephalin-degrading enzymes from longitudinal muscle layer of bovine small intestine

1985 ◽  
Vol 34 (17) ◽  
pp. 3179-3183 ◽  
Author(s):  
Tadahiko Hazato ◽  
Mariko Shimamura ◽  
Ryoichi Kase ◽  
Mikio Iijima ◽  
Takashi Katayama
Keyword(s):  
Small Intestine ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Longitudinal Muscle Layer ◽  
Degrading Enzymes ◽  
Bovine Small Intestine

Diameter changes in arteriolar networks of contracting skeletal muscle

1991 ◽  
Vol 260 (3) ◽  
pp. H662-H670 ◽  
Author(s):  
L. R. Dodd ◽  
P. C. Johnson
Keyword(s):  
Muscle Contraction ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Vascular Tone ◽  
Sartorius Muscle ◽  
Special Importance ◽  
Third Order ◽  
Sympathetic Nerve Stimulation ◽  
Resistance Change ◽  
The Third

The effect of muscular contraction on vessel diameter was studied in the arteriolar network of the exteriorized cat sartorius muscle during normal and elevated vascular tone. Dilation during 4 Hz motor-nerve stimulation was proportionately greatest in the third-order (transverse) arterioles and in vessels immediately upstream and downstream (P less than 0.01). This pattern of dilation was maintained with increased contraction frequency (30 Hz) and during concurrent sympathetic nerve stimulation (8 Hz). The pattern of constriction with sympathetic nerve stimulation alone showed a similar trend with the greatest response in the third-order and adjacent vessels. A model developed to estimate the resistance distribution in the arteriolar network, using data from earlier micropressure and vascular architecture studies in the sartorius muscle, allowed calculation of the resistance change during muscle contraction and sympathetic stimulation. Model predictions indicate that the third-order and adjacent vessels are the greatest site of resistance with both normal and elevated vascular tone. Thus these vessels were the site of greatest resistance change during muscle contraction. The more proximal, arcade vessels made lesser contributions to overall resistance changes, whereas the most distal, fifth-, and sixth-order arterioles appear not to be important in this regard. These findings indicate the third-order, transverse, arterioles are of special importance in regulating blood flow in the sartorius muscle.

Proteolytic Inactivation of Substance P and Neurokinin A in the Longitudinal Muscle Layer of Guinea Pig Small Intestine

2006 ◽  
Vol 47 (3) ◽  
pp. 856-864 ◽  
Author(s):  
R. Nau ◽  
G. Schäfer ◽  
C. F. Deacon ◽  
T. Cole ◽  
D. V. Agoston ◽  
...  
Keyword(s):  
Small Intestine ◽  
Substance P ◽  
Guinea Pig ◽  
Longitudinal Muscle ◽  
Muscle Layer ◽  
Neurokinin A ◽  
Longitudinal Muscle Layer

Antagonism of vasoconstriction by muscle contraction differs with alpha-adrenergic subtype

1993 ◽  
Vol 264 (3) ◽  
pp. H892-H900 ◽  
Author(s):  
L. R. Dodd ◽  
P. C. Johnson
Keyword(s):  
Muscle Contraction ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Sympathetic Nerves ◽  
Second Order ◽  
Sartorius Muscle ◽  
Receptor Subtypes ◽  
Sympathetic Nerve Stimulation ◽  
Adrenergic Antagonist ◽  
Prejunctional Inhibition

It has been suggested that muscle contraction causes prejunctional inhibition of transmitter release from sympathetic nerves. In accordance with this, we found that second-order (50 microns ID) arterioles of the cat sartorius muscle dilate 40-80% more with muscle contraction during 2-, 4-, or 8-Hz sympathetic nerve stimulation than during equivalent constriction produced by intravenous norepinephrine injection. However, when constriction was to the selective alpha 1-agonist phenylephrine, the magnitude of dilation induced by muscle contraction was similar to that seen with sympathetic nerve stimulation, suggesting that prejunctional inhibition is not involved. Alternatively, different receptor subtypes may be activated by sympathetic nerve stimulation and exogenous norepinephrine. In support of this explanation, we found that approximately 50% of the vasoconstrictor effect of sympathetic nerve stimulation (8 Hz) was blocked by prazosin, an alpha 1-adrenergic antagonist, but no further diminution of tone was seen with addiction of yohimbine, an alpha 2-adrenergic antagonist. In contrast, the vasoconstrictor response to exogenous norepinephrine was not affected by prazosin, while addition of yohimbine almost completely blocked the response. These findings suggest that muscle contraction selectively attenuates vasoconstriction mediated by junctional receptors in second-order arterioles.

Longitudinal contractions in the duodenum: their fluid-mechanical function

1975 ◽  
Vol 228 (6) ◽  
pp. 1887-1892 ◽  
Author(s):  
J Melville ◽  
E Macagno ◽  
J Christensen
Keyword(s):  
Longitudinal Muscle ◽  
Circular Muscle ◽  
Muscle Layer ◽  
Slow Waves ◽  
Longitudinal Muscle Layer ◽  
Circular Muscle Layer ◽  
Model Flow ◽  
Displacement Wave ◽  
Marked Points

The hypothesis examined was that contractions of the longitudinal muscle layer occurin the duodenum which are independent of those of the circular muscle layer and that they induce flow of duodenal contents. A segment of opossum duodenum isolated in vitro was marked and photographed during periods of longitudinal muscle contraction, when the circular muscle layer appeared inactive. The prequency of longitudinal oscillation of the marked points was 20.5 cycles/min. The longitudinal displacement wave spread caudad with an average velocity of 3.27 cm/s. Frequency and velocity of electrical slow waves were determined in similiar duodenal segments. Slow-wave frquencywas 18.9 cycles/min. In a two-dimensional mechanical model, flow induced by simulatedlongitudinal muscle layer appear to be driven by the electrical slow waves of the duodenum. They are capable of inducing a pattern of flow in which ocntents flow betweenthe core and the periphery of the intestinal conduit.

Effect of Sympathetic Nerve Stimulation on Cutaneous Small Vein and Small Artery Pressures, Blood Flow and Hindpaw Volume in the Dog

1956 ◽  
Vol 185 (3) ◽  
pp. 453-464 ◽  
Author(s):  
William D. Kelly ◽  
Maurice B. Visscher
Keyword(s):  
Blood Flow ◽  
Nerve Stimulation ◽  
Sympathetic Nerve ◽  
Cardiac Contraction ◽  
Intraluminal Pressure ◽  
Small Artery ◽  
Sympathetic Nerve Stimulation ◽  
Abrupt Decrease ◽  
Average Value ◽  
Small Vein

Electrical stimulation of the lumbar sympathetic chain in dogs produced a variety of response patterns in pressures measured in the femoral artery, a small cutaneous artery (saphenous) and a small cutaneous vein. The preponderant response in the small vein during stimulation was a rise from an average control value of 17 mm Hg to an average value of 30 mm Hg. Shortly after cessation of stimulation a secondary pressure rise occurred to an average value of 42 mm Hg. The average small artery pressure changed from 99 mm Hg to 138 mm Hg during stimulation and fell to 55 mm Hg shortly after stimulation ended. Both pressures then gradually returned to control levels. Hindpaw volume and saphenous artery blood flow invariably showed an abrupt decrease during sympathetic nerve stimulation. An increase in small vein pressure associated with decreased blood flow is interpreted to be due to an increase in resistance to run off from the venous bed. Marked increases in small vein pressure occurred following sympathetic stimulation for as long as ten minutes after cessation of respiration and cardiac contraction. Control experiments excluded changes in cardiac output, central venous pressure and skeletal muscle movement as significant factors in the observed changes. Therefore the small veins as well as the small arteries of the skin of the hindpaw in the dog are capable of constricting in response to sympathetic nerve stimulation to produce marked increases in intraluminal pressure. The small vein can react independently of the small artery.

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