Browsing by Subject "Zebrafish"

Histamine receptors are known to be expressed throughout the peripheral nervous system and are involved in regulating the gut and immune system. The gut-brain axis, which consists of bidirectional signaling between the central nervous system and gastrointestinal tract, links gut functions to emotional and cognitive controls in the brain. Many animal models are known to express histamine receptors in their gut and brain tissue which can be altered by a compromised gut-brain axis like stress. Histamine receptors also play an important role in many gastric and intestinal disorders. However, the precise expression pattern of histamine receptors in zebrafish gut tissue is unknown, as is whether their expression levels also change with stress. Here, I show that zebrafish gut contains several histamine receptors, but their role involving stress within the gut remains unknown. I found that histamine receptors hrh1 and hrh3 as well as the enzyme that synthesizes histamine, histidine decarboxylase (hdc), are expressed in zebrafish gut and brain in wildtype and hdc knockout adult zebrafish using in situ hybridization. Stress induction on wildtype male zebrafish through chronic social defeat and analysis of histamine receptor and hdc mRNA levels using quantitative real time PCR showed no differences in subordinate, dominate, or control fish. However, it did provide quantitative data that hrh1, hrh2, and hdc mRNA expresses in the adult gut. My results demonstrate the first data to suggest histamine receptors are expressed in zebrafish gut, and that even though stress can alter the gut-brain axis, it may not do so through the regulation of these receptors.