Parabrachial Calca neurons influence aversive and appetitive taste function

Area of Science:

• Neuroscience
• Sensory Biology
• Behavioral Science

Background:

• The parabrachial (PB) nucleus is crucial for taste processing and sensory integration.
• PB neurons expressing the Calca gene are implicated in sensory-integrative responses, but their specific role in taste perception is not well understood.

Purpose of the Study:

• To investigate the impact of chemogenetically inhibiting PB Calca neurons on orosensory preferences for bitter and sweet taste stimuli in mice.
• To explore sex-specific roles of PB Calca neurons in taste-guided behaviors.

Main Methods:

• Chemogenetic manipulation using Cre-dependent viral vectors to express the inhibitory designer receptor hM4Di in PB Calca neurons of Calca-Cre mice.
• Brief-access fluid exposure tests were conducted to measure licking behavior towards quinine, cycloheximide, and sucrose solutions.
• Behavioral experiments were performed after administration of clozapine-N-oxide (CNO) to activate the hM4Di receptor.

Main Results:

• Inhibition of PB Calca neurons led to reduced avoidance of quinine, but not cycloheximide, suggesting differential effects on bitter taste perception.
• Male mice with inhibited PB Calca neurons exhibited a selective decrease in licking preference for sucrose.
• These findings indicate that PB Calca neurons modulate responses to both aversive and appetitive taste stimuli, with sex-dependent effects on sweet taste.

Conclusions:

• PB Calca neurons play a significant role in regulating orosensory preferences and taste-guided behaviors.
• The function of PB Calca neurons in appetitive taste processing is sex-dependent.
• These neurons contribute to the integration of taste information with other sensory modalities.