Intraganglionic laminar endings are mechano-transduction sites of vagal tension receptors in the guinea-pig stomach
Article first published online: 5 AUG 2004
The Journal of Physiology
Volume 534, Issue 1, pages 255–268, July 2001
How to Cite
Zagorodnyuk, V. P., Chen, B. N. and Brookes, S. J. H. (2001), Intraganglionic laminar endings are mechano-transduction sites of vagal tension receptors in the guinea-pig stomach. The Journal of Physiology, 534: 255–268. doi: 10.1111/j.1469-7793.2001.00255.x
- Issue published online: 5 AUG 2004
- Article first published online: 5 AUG 2004
- (Received 31 October 2000; accepted after revision 6 March 2001)
- 1Distension-sensitive vagal afferent fibres from the cardiac region of the guinea-pig stomach were recorded extracellularly, then filled with biotinamide, using an anterograde tracing technique.
- 2Most of the stretch-sensitive units of the guinea-pig stomach (41 out of 47; number of animals N= 26) had low thresholds (less than 1 mm) to circumferential stretch and showed slow adaptation. Twenty of these units fired spontaneously under resting conditions (mean: 1.9 ± 0.3 Hz, n = 20, N = 14).
- 3Adaptation of firing during slow or maintained stretch correlated closely with accommodation of intramural tension, but tension-independent adaptation was also present.
- 4Nicardipine (3 μm) with hyoscine (3 μm) reduced stretch-evoked firing of gastric vagal afferents, by inhibiting smooth muscle contraction. Gadolinium (1 mm) blocked distension-evoked firing.
- 5Focal stimulation of the stomach muscle wall with a von Frey hair (0.4 mN) identified one to six punctate receptive fields in each low threshold vagal distension-sensitive afferent. These were marked on the serosal surface of the stomach wall.
- 6Anterograde filling of recorded nerve trunks revealed intraganglionic laminar endings (IGLEs) within 142 ± 34 μm (n = 38; N = 10) of marked receptive fields. The mean distance from randomly generated sites to the nearest IGLE was significantly greater (1500 ± 48 μm, n = 380, N = 10, P < 0.0001). Viscerofugal nerve cell bodies, intramuscular arrays and varicose axons were not associated with receptive fields. The results indicate that IGLEs are the mechanotransduction sites of low threshold, slowly adapting vagal tension receptors in the guinea-pig upper stomach.