Hindbrain catecholamine neurons mediate consummatory responses to glucoprivation

Area of Science:

• Neuroscience
• Physiology
• Behavioral Science

Background:

• Norepinephrine (NE) and epinephrine (E) neurons are vital for ingestive behaviors.
• Previous studies implicated these neurons in appetitive responses to glucoprivation.

Purpose of the Study:

• To investigate the role of NE and E neurons in the consummatory phase of glucoprivic feeding.
• To assess the necessity of these neurons for both appetitive and consummatory ingestive responses to various challenges.

Main Methods:

• Utilized a specific immunotoxin (DSAP) to selectively lesion NE and E neurons projecting to the medial hypothalamus.
• Assessed feeding responses to glucoprivation (insulin, 2-deoxy-D-glucose), fatty acid oxidation blockade (mercaptoacetate), saline infusion, and food deprivation in lesioned rats.

Main Results:

• DSAP-lesioned rats showed impaired appetitive and consummatory feeding responses to glucoprivic challenges.
• Lesioned rats maintained normal ingestive responses to food deprivation and fatty acid oxidation blockade.
• The results indicate a selective impairment of glucoprivic feeding control, not general feeding deficits.

Conclusions:

• Multilevel terminations of catecholamine neurons coordinate both appetitive and consummatory responses to glucoprivation.
• These neurons are essential for the specific control of feeding behaviors triggered by low glucose levels.