ISSN:
1573-7446
Keywords:
abomasal antrum
;
afferent activity
;
impulses
;
mechanoreceptors
;
sheep
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Unitary impulse activity from tension receptors in the abomasal antrum in sheep anaesthetized with chloralose was studied with concurrent measurements of isometric tension in the antral wall, intraluminal pressures and electromyography (EMG). Rhythmical background activity had a close correlation with intraluminal pressure changes and usually a close correlation with local increases in EMG activity and isometric tension. Impulse frequencies increased, but were not sustained, following changes from isotonic to isometric conditions. Tension receptors were excited by transmural compression, by antral distension and by local intra-arterial injections of acetylcholine (2.5–25 µg), pentagastrin (10–20 µg), 5-hydroxytryptamine (1–20 µg), adrenaline (10 µg) cholecystokinin-8 (1–5 µg) or bradykinin (0.5–20 µg), and by systemic injections of bethanecol (5–1000 µg). Local intra-arterial perfusions of atropine (50 µg) and hexamethonium (100 µg) did not abolish spontaneous antral movements or affect the enhanced impulse activity evoked by acetylcholine or 5-hydroxytryptamine. Most antral tension receptors were excited by increases in antral tension or passive distension; they therefore functioned ‘in series’ with the muscularis externa. The discharges of three tension receptors were ‘off-loaded’ early during the contraction evoked by local injections of pentagastrin (10–20 µg).
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01839272
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