Seeking Satiety: Dopamine Receptors 1,2 mRNA Expression in Channel Catfish

Abstract

The dopaminergic nervous system regulates pathways of reward, pleasure, and satiety, and is therefore strongly related to food intake and subsequent eating behavior in mammals. Pathologies of this system have been well‐studied in both humans and rodents; however, little is known about this system in fish species, including channel catfish. To increase our understanding in the involvement of the dopaminergic nervous system in regulation of food intake in fish species, the expression of dopamine receptors 1 and 2 (DR1‐2) mRNA, and their modulation in response to changes in food intake was examined. Samples of the brain, hypothalamus, liver, muscle, spleen, kidney, and two segments of intestine were collected from three fish to examine the tissue distribution of DR1 and DR2 mRNA. In addition, the expression of DR1 and DR2 mRNA was examined in four segments of the channel catfish brain. DR1 and DR2 mRNA was detected across all tissues examined, with readily detectable expression in the brain and hypothalamus. Among brain segments, DR2 mRNA was most readily detectable in the hypothalamus and forebrain. Hypothalamic expression of DR1 and DR2 mRNA was unaffected by food exposure when samples were taken at one‐hour prior to feeding, at the time of feeding, and one‐hour post feeding. Currently, we are examining the expression of DR1 and DR2 mRNA in relation to feeding frequency, as well as prolonged fasting to further elucidate the relationship between food intake and dopaminergic neuron function.Support or Funding InformationK‐INBRE P20GM103418