Assessment of true splanchnic glucoreceptors in the jejuno-ileum of the cat

In anesthetized cats, the unitary activity of splanchnic sensory neurons were recorded from T9, T10 and T11 spinal ganglia by means of extracellular glass microelectrodes. Twelve neurons, generally silent, were activated by perfusion of jejuno-ileum with glucose solutions (10, 50, 100 or 200 g/l). The responses indicated that the corresponding receptors belonged to the slowly adapting type. The discharge frequencies were always low (less than 10 Imp/sec), but varied according to the glucose concentration. Saline solutions (NaCl having the same osmotic pressure as glucose ones), acid solutions (HCl, pH 2.7), or mechanical stimulation were unable to stimulate them. These neurons must be associated with true glucoreceptors. These receptors were connected via non-myelinated fibres (conduction velocities-0.8-2.4 m/sec). It is concluded that these splanchnic glucoreceptors are similar to vagal glucoreceptors described previously.