Abstract
1. The effect of surgical transection and reunion of the small bowel on its pacesetter potenial (PP) frequency gradient was studied over periods of 3 months in six conscious, healthy dogs, using fourteen platinum electrodes previously implanted along the bowel.
2. Duodenal transection and reunion abolished the gradient of the pacesetter potential distal to the transection and this effect persisted throughout 3 months of observation.
3. In dogs with two transections, one in the duodenum and another in the mid small bowel, the mid small bowel transection and reunion further reduced the frequency of the PP caudad to it and this effect also persisted throughout the 3 months of observation.
4. We conclude that the gradient in intact bowel occurs because the frequency of the duodenal pace-maker is considerably more rapid than the natural frequency of the PP in the rest of the bowel, and because the bowel is composed of collections or populations of smooth muscle cells with differing natural or intrinsic PP frequencies arranged in a progression of diminishing frequencies from orad to caudad location. The natural frequency of a segment is unmasked by transection of the bowel just orad to it because this eliminates the influence or drive of the orad pace-maker. The findings are in agreement with the concept that in intact bowel, as the PP passes caudadward, distal populations of cells are eventually encountered which cannot follow the faster orad pacesetter because of the slowness of their natural frequency. Thus, during caudad passage, some cycles of the PP are not transmitted and this, occurring over the length of the bowel, accounts in part, at least, for the gradient of frequency of PP over the small bowel.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- ARMSTRONG H. I., MILTON G. W., SMITH A. W. Electropotential changes of the small intestine. J Physiol. 1956 Jan 27;131(1):147–153. doi: 10.1113/jphysiol.1956.sp005451. [DOI] [PMC free article] [PubMed] [Google Scholar]
- BASS P., CODE C. F., LAMBERT E. H. Motor and electric activity of the duodenum. Am J Physiol. 1961 Aug;201:287–291. doi: 10.1152/ajplegacy.1961.201.2.287. [DOI] [PubMed] [Google Scholar]
- BASS P., WILEY J. N. EFFECTS OF LIGATION AND MORPHINE ON ELECTRIC AND MOTOR ACTIVITY OF DOG DUODENUM. Am J Physiol. 1965 May;208:908–913. doi: 10.1152/ajplegacy.1965.208.5.908. [DOI] [PubMed] [Google Scholar]
- BASS P., WILEY J. N. ELECTRICAL AND EXTRALUMINAL CONTRACTILE-FORCE ACTIVITY OF THE DUODENUM OF THE DOG. Am J Dig Dis. 1965 Mar;10:183–200. doi: 10.1007/BF02233747. [DOI] [PubMed] [Google Scholar]
- Bunker C. E., Johnson L. P., Nelsen T. S. Chronic in situ studies of the electrical activity of the small intestine. Arch Surg. 1967 Aug;95(2):259–268. doi: 10.1001/archsurg.1967.01330140097023. [DOI] [PubMed] [Google Scholar]
- DANIEL E. E., CARLOW D. R., WACHTER B. T., SUTHERLAND W. H., BOGOCH A. Electrical activity of the small intestine. Gastroenterology. 1959 Sep;37:268–281. [PubMed] [Google Scholar]
- DOUGLAS D. M. The decrease of frequency of contraction of the jejunum after transplantation to the ileum. J Physiol. 1949 Dec 15;110(1-2):66–75. doi: 10.1113/jphysiol.1949.sp004421. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Diamant N. E., Bortoff A. Nature of the intestinal slow-wave frequency gradient. Am J Physiol. 1969 Feb;216(2):301–307. doi: 10.1152/ajplegacy.1969.216.2.301. [DOI] [PubMed] [Google Scholar]
- MILTON G. W., SMITH A. W. The pacemaking area of the duodenum. J Physiol. 1956 Apr 27;132(1):100–114. doi: 10.1113/jphysiol.1956.sp005505. [DOI] [PMC free article] [PubMed] [Google Scholar]
- McCoy E. J., Baker R. D. Intestinal slow waves: effect of transection on propagation velocity. Proc Soc Exp Biol Med. 1968 Nov;129(2):562–563. doi: 10.3181/00379727-129-33369. [DOI] [PubMed] [Google Scholar]
- Nelsen T. S., Becker J. C. Simulation of the electrical and mechanical gradient of the small intestine. Am J Physiol. 1968 Apr;214(4):749–757. doi: 10.1152/ajplegacy.1968.214.4.749. [DOI] [PubMed] [Google Scholar]