Distribution of serotonin 5-HT 1A -binding sites in the brainstem and the hypothalamus, and their roles in 5-HT-induced sleep and ingestive behaviors in rock pigeons ( Columba livia )

Comparing the Expression of Genes Related to Serotonin (5-HT) in C57BL/6J Mice and Humans Based on Data Available at the Allen Mouse Brain Atlas and Allen Human Brain Atlas

“…Likewise, alterations have been reported in the pattern of expression for the HTR1A and HTR2A genes in mental illnesses related to mood and response to stress [51, 52], panic attacks, [53], bipolar disorder, anxiety, and depression, among others [54–56], but not in behaviors such as suicide [49]. Reports of expression of the 5-HT1A receptor in the hippocampus, cortex, and hypothalamic regions correspond to the expression reported in this study [16, 55]. Other sources that provide data on serotonin genes are postmortem studies that report increases in genes such as HTR2A in patients with conditions such as depression and schizophrenia [54, 57, 58].…”

“…They have helped refine anatomical [4, 9, 11, 14, 15], taxonomical [9, 16, 17], and statistical methods [18], which allow us to partly identify the relationship between structures and functions upon examining expression patterns [4, 14, 15, 19] and compare expression levels in different states [20] and anatomical correlations and phenotypes between different species [5, 14, 15, 18, 19]. …”

“…Serotonin or 5-hydroxytryptamine (5-HT) was chosen as the focus of this study for various reasons: first, because many behavioral disorders and the drugs used to treat them have been linked to serotonergic mechanisms [27, 38–40]; second, 5-HT projections and receptors have been described in multiple sites [14–16, 27], facilitating the search for the expression of related genes. Given that a broad area of research in psychobiology and behavioral neuroscience is the use of animal models, it is of interest to compare the distribution of serotonin-related gene expression, as this may help confirm the validity of interspecies models, in this case mouse-human [17, 41].…”

“…Changes in its synthesis, bioavailability, and expression of receptors and other molecules related to its functioning have been associated with changes in behavior [12, 17, 27]. Many clinical conditions have been linked to altered serotonergic functions, including eating disorders, anxiety, issues with endocrine and circadian rhythm regulation, perception problems, compulsive behavior, pain, schizophrenia, sexual dysfunction, sleep disorders, and depression [12, 16, 27, 42, 43]. …”

Identification and functional characterisation of 5-HT4 receptor in sea cucumber Apostichopus japonicus (Selenka)

“…Aside from 5-HT3, which is a ligand-gated ion channel that belongs to the nicotinic acetylcholine receptor superfamily7, the 5-HT receptors belong to the superfamily of G protein coupled receptors (GPCRs)89. Orthologous G protein-coupled 5-HT receptors have been identified and functionally characterised in deuterostomes including humans10, mammals11, birds12 and fishes13, and in protostomes including nematodes14, crustaceans15 and insects1617. Furthermore, these G protein-coupled 5-HT receptors are mainly classified in three groups: (1) 5-HT1 and 5-HT5 receptors that couple preferentially to Gi proteins and inhibit cAMP synthesis, (2) 5-HT2 receptors that activate Gq proteins, which mediate the hydrolysis of inositol phosphates and cause a subsequent increase in cytosolic Ca 2+ , and (3) 5-HT4, 5-HT6, and 5-HT7 receptors that couple to Gs proteins and promote cAMP formation1819.…”