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9208119 
Journal Article 
Synchronized network oscillations in rat tuberoinfundibular dopamine neurons: switch to tonic discharge by thyrotropin-releasing hormone 
Lyons, DJ; Horjales-Araujo, E; Broberger, C; , 
2010 
1 
Neuron
ISSN: 0896-6273
EISSN: 1097-4199 
CELL PRESS 
CAMBRIDGE 
217-229 
English 
20152128 
WOS:000274136100009 
The pituitary hormone, prolactin, triggers lactation in nursing mothers. Under nonlactating conditions, prolactin secretion is suppressed by powerful inhibition from hypothalamic tuberoinfundibular dopamine (TIDA) neurons. Although firing pattern has been suggested as integral to neuroendocrine control, the electrical behavior of TIDA cells remains unknown. We demonstrate that rat TIDA neurons discharge rhythmically in a robust 0.05 Hz oscillation. The oscillation is phase locked between neurons, and while it persists during chemical synaptic transmission blockade, it is abolished by gap junction antagonists. Thyrotropin-releasing hormone (TRH) potently stimulates prolactin release, an effect assumed to take place in the pituitary. In TIDA cells, TRH caused a transition from phasic to tonic firing through combined pre- and postsynaptic effects. These findings suggest a model for prolactin regulation where a TIDA network switch from oscillations to sustained discharge converts dopamine from an antagonist at high concentrations to a functional agonist as dopamine output from the network decreases.