The effects of vagotomy and splanchnotomy on gastric motility in the sheep

Duncan, Dorothy L.

doi:10.1113/jphysiol.1953.sp004836

Cited by 45 publications

(45 citation statements)

References 9 publications

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“…The complex gastric movements are dependent upon reflexes with afferent and efferent pathways in the vagi (Iggo, 1951(Iggo, , 1956Duncan, 1953;Titchen, 1953Titchen, , 1958Titchen, , 1960Reid & Titchen, 1965). The reflex centre is in the hind-brain (Iggo, 1951;Andersson, Kitchell & Persson, 1959).…”

Section: Introductionmentioning

confidence: 99%

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

Iggo¹,

Leek²

1967

The Journal of Physiology

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SUMMARY1. A method for obtaining reticulo-ruminal movements for up to 19 hr in halothane-anaesthetized sheep is described. The duration, wave form and frequency of the movements resembles those in the conscious animal except that ruminal movements have a lower amplitude.2. A method of recording for up to 51 hr single efferent unit discharges from fibres presumed to innervate the reticulo-rumen is described.3. At least seven distinguishable types of discharge pattern were recorded. By relating these temporally to movements of the reticulum and rumen it was concluded that Types I, II and III occurred in fibres innervating the reticulum or associated structures, Type IV the rumen and Types V, VI and VII other gastric structures not yet identified. Apart from Type VII units there was no 'resting discharge' in efferent fibres during the quiescent phase of the gastric cycle.4. We conclude that the co-ordination of the complex sequence of gastric movements in ruminant animals is a function of the 'gastric centres' in the hind-brain through their ability to determine the pattern, durations, spike frequencies and temporal interrelationships of discharges in gastric motoneurons innervating the different parts of the forestomach.

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Section: Introductionmentioning

confidence: 99%

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

Iggo¹,

Leek²

1967

The Journal of Physiology

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“…This innervation is of much greater importance in ruminants than in other species [11]. Since the abomasum retains considerable activity after vagotomy, the importance of its innervation contrasts markedly with that of the forestomach [5]. In the milk-fed calf, the abomasum has a more important role in digestion than the still undeveloped forestomach.…”

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The Effects of Vagotomy on the Abomasum in Calves: Radiography and Protein Gene Product 9.5 Immunohistochemistry.

Soehartono

Yamada

Yamagishi

et al. 2001

The Journal of Veterinary Medical Science

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ABSTRACT. Abomasal disorders of calves with total vagotomy, operated on at 1 week old, were investigated with radiography and protein gene product (PGP) 9.5 immunohistochemistry. Radiographic findings indicated abomasal atony with dilatation in all calves 2 weeks after vagotomy, while 4 weeks after vagotomy abomasal dilatation was detected in 2 calves and another 2 calves showed dilatation and impaction. The densities of PGP 9.5-immunoreactive nerves in the tunica muscularis decreased significantly in the corpus region of the greater curvature 2 weeks after vagotomy and in the pyloric region of the lesser curvature 4 weeks after vagotomy, and it was at its lowest 4 weeks after vagotomy in all regions examined. In conclusion, abomasal dilatation and/or impaction in vagotomized calves confirmed by radiography were related with a decreased frequency of nerves in the tunica muscularis of the abomasum. KEY WORDS: abomasal disorder, PGP 9.5, vagotomy.J. Vet. Med. Sci. 63(6): 671-674, 2001 Gastric motility is greatly influenced by the vagus nerves whose activity is integrated by gastric centers in the medulla oblongata [6,18]. This innervation is of much greater importance in ruminants than in other species [11]. Since the abomasum retains considerable activity after vagotomy, the importance of its innervation contrasts markedly with that of the forestomach [5]. In the milk-fed calf, the abomasum has a more important role in digestion than the still undeveloped forestomach. The vagus may control abomasal motility through its innervation of the tunica muscularis. Mechanical malfunction of the abomasum in cattle might involve the disorder of vagal innervation through the dorsal and ventral vagal nerves which ramify to the abomasum [2]. Although a vagal nervous dysfunction has been suggested as a possible cause of abomasal disorders [16], vagal nerve injury in the abomasal wall is still uncertain. The distribution of vagal nerve endings in the sheep stomach has been reported after short-term vagotomy [15], however, the long-term effects of vagotomy on the mural innervation of the ruminant stomach have not been described.Radiographic studies of the abomasum of lambs and calves before and after vagotomy were mostly undertaken during motility [17] and abomasal emptying [1]. The former was a short-term investigation while the latter maintained the calf after vagotomy by cannulation feeding into the abomasum. The radiography of the long-term effects of vagotomy on the abomasum maintained with normal feeding has not yet been reported. Furthermore, radiographic findings on the functional state of the abomasum have not yet been compared with the histology of the regulatory systems in the abomasal wall.Protein gene product 9.5 (PGP) is a neuronal soluble protein distributed in the central and peripheral nervous systems of different animals [14,20]. It is useful as a general immunohistochemical marker for nervous elements and for the assessment of neuronal development and the detection of neuronal damage in diseases of the nervo...

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“…The verification of these histological findings by physiological methods has been rarely attempted. The single exception seems to be Laughton (1929) who showed that, in the cat, faradic stimulation of the floor of the fourth ventricle overlying the dorsal motor nucleus produced increased gastric motility.The importance of the vagal nerves and medullary reflex centres in the neural control of the reticulum, rumen and oesophagus has often been demonstrated (see Duncan, 1953). It has been suggested that the posterior brain stem contains a 'reticulo-ruminal centre' (Iggo, 1951).…”

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“…The importance of the vagal nerves and medullary reflex centres in the neural control of the reticulum, rumen and oesophagus has often been demonstrated (see Duncan, 1953). It has been suggested that the posterior brain stem contains a 'reticulo-ruminal centre' (Iggo, 1951).…”

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Localization of regions in the medulla oblongata of sheep associated with rumination

Bell¹,

Lawn²

1955

The Journal of Physiology

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It is generally accepted that the motor fibres to the stomach and oesophagus originate in the dorsal nucleus of the vagus (Kuntz, 1953). Furthermore, attempts have been made to show that the efferent fibres to the stomach and oesophagus are derived from localized groups of cells within the dorsal nucleus. In order to demonstrate such specific topographical grouping of cells, most workers have employed the anatomical method where the vagi are sectioned at various levels and the retrogressive changes in the medullary nuclei studied later. The data available from such studies have been reviewed by Molhant (1910) and more recently by Mohiuddin (1953), the latter commenting on the limitations and contradictions of the method. The verification of these histological findings by physiological methods has been rarely attempted. The single exception seems to be Laughton (1929) who showed that, in the cat, faradic stimulation of the floor of the fourth ventricle overlying the dorsal motor nucleus produced increased gastric motility.The importance of the vagal nerves and medullary reflex centres in the neural control of the reticulum, rumen and oesophagus has often been demonstrated (see Duncan, 1953). It has been suggested that the posterior brain stem contains a 'reticulo-ruminal centre' (Iggo, 1951). This paper gives an account of experiments undertaken to delimit the regions within the medulla oblongata from which contraction of the reticulum, rumen and oesophagus can be obtained by electrical stimulation. METHODSNineteen adult Blackface x Kent sheep were used. The weights varied between 25 and 47 kg, the group included twelve females, the seven males were castrates.Anaesthesia was induced by the injection of thiopentone sodium into the recurrent tarsal vein, about 25 mg/kg initially, with supplements as required. After preparation anaesthesia was maintained with 05 % chloralose. The head was firmly secured in a head holder, the medulla exposed and the cerebellum removed by suction to expose the fourth ventricle. Body temperature was maintained within normal limits.

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The effects of vagotomy and splanchnotomy on gastric motility in the sheep

Cited by 45 publications

References 9 publications

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

An electrophysiological study of single vagal efferent units associated with gastric movements in sheep

The Effects of Vagotomy on the Abomasum in Calves: Radiography and Protein Gene Product 9.5 Immunohistochemistry.

Localization of regions in the medulla oblongata of sheep associated with rumination

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