To provide feeding-related neurochemical and behavioral characterization of globus pallidus (GP) neurons, extracellular single neuron activity was recorded in the GP of alert rhesus monkeys by means of carbon-fibre multibarreled glass microelectrodes during: (1) microelectrophoretic administration of chemicals (glucose, catecholamines, Ach, GABA and excitatory amino acids) and (2) performance of a conditioned alimentary task. A high proportion, 17%, of all pallidal cells tested proved to be glucose-sensitive (GS), i.e. were suppressed in activity by microelectrophoretically applied glucose. Predominantly these GS neurons were those that displayed differential responses while the animal was presented with food vs. nonfood objects. GS cells, and less characteristically the glucose-insensitive neurons, exhibited complex firing rate patterns during the discriminative conditioned feeding task. These above subsets of pallidal neurons showed differential neurotransmitter sensitivities in the microiontophoretic studies. The present results, along with previous data, indicate that chemosensitive cells of the GP are under multiple neurotransmitter modulation and belong to the central glucose monitoring neural network integrating various feeding-associated sensory, motor, perceptual and motivational signals.
ASJC Scopus subject areas
- Nutrition and Dietetics