Raphe serotonin projections dynamically regulate feeding behavior through targeting inhibitory circuits from rostral zona incerta to paraventricular thalamus

Repeated low doses of psilocybin increase resilience to stress, lower compulsive actions, and strengthen cortical connections to the paraventricular thalamic nucleus in rats

“…Online surveys in human microdosers have reported changes in sleep patterns (6), which might conceivably be mediated by increased 5-HT7 receptor levels in the PVT, as seen in the microdosing rats. The PVT is innervated by serotonergic neurons from the dorsal raphe nucleus (42), and by descending axons arising from pyramidal neurons in the frontal cortex both in humans (43) and rats (44). Increased input from these structures might lead to locally increased synaptic density through cortico-thalamic long-term potentiation (45).…”

Multiple cholinergic receptor subtypes coordinate dual modulation of acetylcholine on anterior and posterior paraventricular thalamic neurons

“…around −50 mV and the firing rates before drug application at 0.5-1.0 Hz. Following a criteria used for our previous studies (Barrett et al, 2021;Ye et al, 2022b), we categorized recorded neurons into ACh-excited neurons if the ACh-induced depolarization was more than 1.5 mV and/or the firing rate was increased at least 20% by ACh treatment. Similarly, if the hyperpolarization was more than 1.5 mV and/or the firing rate was decreased at least 20% by ACh treatment, these neurons were classified as ACh-inhibited neurons.…”

“…It has been extensively studied that neurotransmitters and neuromodulators, such as serotonin and oxytocin, modulate PVT neurons for the regulation of motivated behavior and aversive learning using electrophysiological and pharmacological tools together with behavioral paradigms (Barrett et al, 2021;Beas et al, 2018;Ye et al, 2022b;Ye & Zhang, 2021;Zhang & van den Pol, 2017). Our recent studies also reported that dopamine (DA) transmissions from zona incerta (ZI) promote motivated food seeking by inhibiting PVT neurons (Ye et al, 2023).…”

Serotonergic regulation of appetite and sodium appetite

“…34 Another study identified a role of an inhibitory circuit between the rostral zona incerta GABAergic neurons and the paraventricular thalamus that is innervated by the DRN serotonergic neurons to suppress feeding. 35 Therefore, it now appears that DRN serotonergic neurons innervate both hypothalamic and extra-hypothalamic areas of brain to suppress appetite. On the other hand, serotonergic neurons in DRN receive monosynaptic inputs from several nuclei involved in the regulation of energy homeostasis, which includes the paraventricular nucleus of the hypothalamus (PVH), the lateral hypothalamic area (LHA), the dorsomedial nucleus of the hypothalamus (DMH), the arcuate nucleus of the hypothalamus (ARH), the BNST, the central amygdala (CeA), and the parabrachial nucleus (PBN) (Figure 1), according to results from studies using rabies viral tracing.…”

“…However, a recent study demonstrated that DRN serotonergic neurons decrease feeding via redundant innervation of the lateral hypothalamic area (LHA) and the BNST 34 . Another study identified a role of an inhibitory circuit between the rostral zona incerta GABAergic neurons and the paraventricular thalamus that is innervated by the DRN serotonergic neurons to suppress feeding 35 . Therefore, it now appears that DRN serotonergic neurons innervate both hypothalamic and extra‐hypothalamic areas of brain to suppress appetite.…”