[Changes in blood pressure and impulse activity in intestinal nerves during exposure of small intestine...

I. a. administration of threshold concentration (0.2 ml 7.8 mM) of lactic acid into the small intestine was found to increase afferent and efferent impulsation in the intestinal nerves as well as the systemic arterial blood pressure in anesthetized cats. Increase in the lactic acid concentration up to 250 mM/l resulted in two-phasic augmentation of the nerve responses and of the pressor reflexes. In the range from 7.8 to 62.5 mM/l of lactic acid concentration the absolute magnitude of pressor reflexes was 2.3 +/- 0.6--4.2 +/- 0.5 mm Hg. Further increase in the lactic acid concentration (up to 250 mM/l) produced on augmentation in the reflexes magnitude up to 18 +/- 2.8 mm Hg. A possible functional role of afferent impulses generated by the tissue receptors following an increase in metabolites concentration in the organs, is discussed.