Vagal mechanoreceptors of the inferior thoracic oesophagus, the lower oesophageal sphincter and the stomach in the sheep

Falempin, Maurice; Mei, N.; Rousseau, Jean-Paul

doi:10.1007/bf00581145

Cited by 62 publications

(46 citation statements)

References 18 publications

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“…Consequently, it has been proposed to use their discharge recording to analyse the mechanical variations occurring at this level (Mei, Salducci, Monges & Farnarier, 1972;Falempin, Mei & Rousseau, 1978). In the present work, we have developed this technique in order to investigate the effects of oesophageal afferents on the lower oesophageal sphincter activity.…”

Section: Muscular Mechanoreceptorsmentioning

confidence: 99%

Vagal mechanoreceptors located in the lower oesophageal sphincter of the cat.

Clerc¹,

Mei²

1983

The Journal of Physiology

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SUMMARY1. In anaesthetized cats, sixty-two vagal sensory units with afferent endings in the lower oesophageal sphincter were recorded by means of extracellular glass micro-electrodes implanted in the nodose ganglion.2. All the receptors had non-medullated fibres, with conduction velocities ranging from 0O8 to 1-2 m/s. From the direct stimulation of the lower oesophageal sphincter, three types of mechanoreceptors were identified. 3. Thirty-one were activated by natural stimuli: tonic contraction of the sphincter and distension elicited by the passage of a bolus. Artificial stimulation effected by digital compression was also effective. These receptors were similar to muscular endings already described in the-digestive tract. Their main characteristic, i.e. their slow adaptation, suggests that they act as sensors of sphincter opening and closure. This was corroborated by observations obtained during distension of the cervical or thoracic oesophagus; a maximum decrease occurred in the lower oesophageal sphincter mechanoreceptor discharge when the distension was produced between 9 and 12 cm from the lower oesophageal sphincter.4. Twenty-nine endings were found in the superficial layers mucosaee). Contrary to the muscular receptors, the mucosal receptors were not affected by normal contractions or distensions of the lower oesophageal sphincter. They were activated only by strong stimuli like digital compression or distension achieved with a balloon. In addition, mucosal stroking was a potent stimulus. Whatever the stimulus used, the mucosal receptors showed rather rapidly adapting discharges. These receptors should be considered to be sensors of bolus consistency.5. Two mechanoreceptors, located in the serous membrane ofthe lower oesophageal sphincter, were identified by touching or by stretching. Their discharges showed that they belonged to the rapidly adapting type.6. A comparison of the three types of receptors found in the lower oesophageal sphincter is made with known digestive endings and their possible role is discussed.

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Section: Muscular Mechanoreceptorsmentioning

confidence: 99%

Vagal mechanoreceptors located in the lower oesophageal sphincter of the cat.

Clerc¹,

Mei²

1983

The Journal of Physiology

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“…Previous reports have shown that the muscular layers of the stomach contain slowly adapting mechanoreceptors which increase their discharge into afferent vagal nerves fibres during stomach distension (Paintal, 1954;Iggo, 1957;Falempin et al 1978;Cotterel & Iggo, 1984). Other reports have shown the presence of mechanoreceptors in the serosa of the stomach and the adjacent mesentery which may discharge into afferent fibres in the splanchnic nerves and which are involved in nociception (Janig & Morrison, 1986;Grundy & Scratcherd, 1989).…”

Section: Figurementioning

confidence: 99%

Activation of the Renin‐Angiotensin System Contributes to the Peripheral Vasoconstriction Reflexly Caused by Stomach Distension in Anaesthetized Pigs

Molinari

Battaglia

Grossini

et al. 2003

Experimental Physiology

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Gastric distension in anaesthetized pigs reflexly elicits peripheral vasoconstriction and an increase in plasma renin activity (PRA), with vagal afferent and sympathetic efferent limbs. The aim of the present study was to quantify the contribution of the renin‐angiotensin system to the peripheral vasoconstriction. In pigs anaesthetized with α‐chloralose, changes in anterior descending coronary, superior mesenteric and left external iliac blood flow caused by stomach distension before and after blockade of angiotensin II receptors with losartan were assessed using electromagnetic flowmeters. Gastric distension for periods of 30 min was performed by injecting 0.8 l warm Ringer solution into balloons positioned within the viscus. Changes in heart rate and renal blood flow were prevented by atrial pacing and injection of phentolamine into the renal arteries, and changes in regional perfusion pressure and in baroreceptor activity were minimized by aortic constriction and denervation of the carotid sinuses. PRA was assessed by radioimmunoassay of angiotensin I. Before blockade of angiotensin II receptors by administration of losartan, stomach distension decreased coronary blood flow by 14.2% in six pigs and mesenteric and iliac blood flow by 11% and 17.3%, respectively, in another six pigs. After administration of losartan, these decreases were significantly reduced to 7.4%, 6.8% and 8.7%, respectively. The above responses were abolished by bilateral section of the subdiaphragmatic vagal nerves. These results show that the peripheral vasoconstriction reflexly caused by stomach distension was significantly contributed to by the concomitant activation of the renin‐angiotensin system.

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“…A direct association between gastric and/or oesophageal contractions and impulse traffic in vagal efferent neurones has been shown in conscious sheep by the technique ofcrossed-nerve anastomosis (Dussardier, 1955(Dussardier, , 1963Roman, a, b, 1967 and in anaesthetized animals by direct recording of action potentials in vagal efferent fibres (Iggo & Leek, 1967). Evidence obtained from studies on impulse traffic in afferent vagal fibres in the anaesthetized goat or sheep suggests that the cranial regions of the stomach (Iggo, 1955;Leek, 1969Leek, , 1977 and the caudal oesophagus (Falempin, Mei & Rousseau, 1978) are richly provided with mechano-and/or chemoreceptors. Because both in regurgitation of digesta in the course of rumination and eructation of gas there are co-ordinated movements of the oesophagus and of the reticulum and/or rumen (Stevens & Sellers, 1960;Sellers & Stevens, 1966Dougherty, 1968;Rousseau, 1970;Titchen, 1979), it was of interest to follow activity of vagal efferents and afferents during such events.…”

Section: Introductionmentioning

confidence: 99%

Electrophysiological Study of Vagal Afferent and Efferent Units in Conscious Sheep

Rousseau

1984

Exp Physiol

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SUMMARYCrossed-nerve anastomoses were performed to record activity of vagal efferents and afferents during regurgitation and eructation in conscious sheep. Following anastomoses of the central end of a vagus nerve to the peripheral end of a phrenic nerve, discharges in units of the diaphragm reinnervated by vagal efferent neurones were associated with contractions of the caudal oesophagus and of the rumen. During regurgitation in the course of rumination, discharges in oesophageal efferents consisted of a characteristic pattern of two bursts in a constant association with the additional phase of the reticular contraction and the more forceful inspiratory effort. Discharges in two types of units bore a temporal relation with the motor gastric cyles. Early units are interpreted as innervating pillars of the rumen and late units its dorsal wall. Regular patterns of discharge were recorded during successive A sequences of rumen contractions. In contrast, there was a variability of pattern of activity of efferents during B sequences: a constant time relationship was not observed between discharges of both types of units. During B sequences accompanied by eructation, the most characteristic pattern in gastric and oesophageal units had the following features: the impulses in the early units increased in frequency, outlasted the discharge in the late units by 1 s and ended when a brief discharge was recorded in an oesophageal unit at the time of eructation. It is suggested from the patterns of discharge observed in both gastric and oesophageal efferents that the orderly sequence which achieves regurgitation and eructation results from the central co-ordination of efferent output.Following anastomoses of the central root of the nodose ganglion to the peripheral end of the accessory nerve, discharges in units of the mastoido-humeral muscle reinnervated by vagal afferent axons were associated with contractions of the oesophagus and movements of the larynx during swallowing and regurgitation. Discharges in oesophageal afferents coming from the caudal oesophagus were coincident with discharges observed in the vagal efferent fibres innervating this part of the oesophagus. Afferents from the pharynx and the larynx were active at the same time as the nasopharynx and the glottis were demonstrated to be closed. Thus the major characteristic of the afferents the traffic of which has been recorded in cross-sutured sheep in the course of rumination is that their discharges are occurring at the same time as motor events are developing. It has been concluded that in the complex motor events during regurgitation there is a significant afferent input which contributes to the central nervous regulation of their course at any time.

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Vagal mechanoreceptors of the inferior thoracic oesophagus, the lower oesophageal sphincter and the stomach in the sheep

Cited by 62 publications

References 18 publications

Vagal mechanoreceptors located in the lower oesophageal sphincter of the cat.

Vagal mechanoreceptors located in the lower oesophageal sphincter of the cat.

Activation of the Renin‐Angiotensin System Contributes to the Peripheral Vasoconstriction Reflexly Caused by Stomach Distension in Anaesthetized Pigs

Electrophysiological Study of Vagal Afferent and Efferent Units in Conscious Sheep

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