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Influence of the pattern of jejunal distension on mesenteric afferent sensitivity in the anaesthetized rat
- Source :
- Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society. 20(2)
- Publication Year :
- 2007
-
Abstract
- Vagal, spinal and intestino-fugal fibres all potentially transmit mechanosensory afferent information from the gastrointestinal tract. We aimed to characterize the relative mechanosensitivity of these three different afferent populations supplying the rat jejunum. Afferent nerve discharge was recorded from pentobarbitone-anaesthetized rats during different distension protocols. Saline ramp distension (1 mL min(-1)) and barostat ramp distension (2 mmHg 4 s(-1)) each evoked biphasic responses but with the latter significantly attenuated especially at low distending pressures. Barostat controlled phasic distensions (10-50 mmHg, 25 s) evoked an afferent response with a peak at the onset of distension adapting to a plateau level that was maintained and comparable to the barostat ramp responses at the corresponding pressures. Chronic subdiaphragmatic vagotomy significantly attenuated the low pressure component of the response to balloon ramp distension and both peak and plateau responses to phasic distension. Single unit analysis showed an absence of low threshold afferent activity after vagotomy while the response to fibres with wide-dynamic range and high threshold sensitivity were preserved hexamethonium had no effect on the responses to either ramp or phasic distension. These findings suggest that the nature of the distension stimulus is critical in determining the pattern of response observed from the various subpopulations of afferents supplying the bowel wall.
- Subjects :
- Male
Physiology
Manometry
medicine.medical_treatment
Distension
Stimulus (physiology)
Vagotomy
Enteric Nervous System
chemistry.chemical_compound
medicine
Animals
Mesentery
Neurons, Afferent
Rats, Wistar
Saline
Afferent Pathways
Endocrine and Autonomic Systems
business.industry
Gastroenterology
Vagus Nerve
Barostat
Rats
Mechanoreceptor
Electrophysiology
medicine.anatomical_structure
Jejunum
chemistry
Anesthesia
Hexamethonium
business
Mechanoreceptors
Subjects
Details
- ISSN :
- 13501925
- Volume :
- 20
- Issue :
- 2
- Database :
- OpenAIRE
- Journal :
- Neurogastroenterology and motility : the official journal of the European Gastrointestinal Motility Society
- Accession number :
- edsair.doi.dedup.....967c97e30dcd6b2b3a68e4036b0f5591