ISSN:
0095-9898
Keywords:
Life and Medical Sciences
;
Cell & Developmental Biology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Medicine
Notes:
Reflex inhibitions of cardiac and ventilation rates of the crayfish, Procambarus simulans, have been used as indices of chemical sensitivity in an assay of configurational specificity among 30 carbohydrates and related compounds. Cardiac activity was determined from electrocardiograms and the bilateral ventilation frequencies were recorded with low-level pressure transducers. The responses were followed simultaneously on a commercial polygraph. Test solutions were introduced into the region of the branchial chamber with the ventilation stream. Positive responses consisted of inhibition or cessation of activity in both systems.Analysis of results from sugars with various configurations involving carbons 2, 4, and 5 of the pyranose ring indicated these positions were not critical in evoking the responses. Sugars lacking carbon 6, e.g., D-xylose and D-arabinose, were also effective stimuli. Blocking of the -OH at the C1, as found in glycosides, converts a stimulating configuration into a non-stimulating one, except where the substituent contains a free -OH group at the terminal carbon, e.g., maltose or cellobiose. Stimulating disaccharides were all 1-4 glycosides and possessed a free -OH at C1. The disaccharides with linkages other than 1-4 were non-stimulatory, e.g., gentiobiose, trehalose, and melibiose, as were the trisaccharides, raffinose and melizitose. Linear and cyclic polyhydroxy alcohols, e.g., erythritol and inositol, and short chain aldoses, e.g., erythrose, were also ineffective.Stimulation of the receptors seems to require the pyranose ring and access to a free hydroxyl group on C1. Isolation of the receptor and measurement of single unit activity are required before incontrovertible statements of specificity can be made. A basis for such investigations has been made.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jcp.1030650310
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