Pathological glucose tolerance after kainate microlesions of the globus pallidus

To elucidate the effect of neuron-specific pallidal microlesions on the regulation of blood glucose, kainic acid (KA) was microelectrophoretically applied into the ventral-medial subdivision of the pallidum (vmGP), and fasting blood glucose levels (BGLs) as well as glucose tolerance (GT) of the animals were tested. BGLs were slightly increased after bilateral vmGP microlesions. Peak of the glucose curve in the GT test was found at the 18(th)-21(st) min after the start of sugar load in the control rats, whereas a similar peak was observed much later, at the 30(th)-33(rd) min, in the KA lesioned animals. The fall of glucose concentration in these rats was only small and prolonged, with pathologically increased values even at the 120(th) min. The pancreas of all animals was found intact. These and other findings indicate the importance of chemosensory neurons of the vmGP in the central homeostatic-metabolic regulation.