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Hospitalist clinician-educators frequently work with medical students at the clinical level, but many early career educators may lack an understanding of how to effectively promote student learning and growth. We explore the role of hospitalists working with medical students in the clinical environment as it pertains to three overarching domains - clinical skills, systems-based healthcare, and career mentorship.

Histamine H1 receptor (H1R) in the central nervous system plays an important role in various functions, including learning and memory, aggression, feeding behaviors, and wakefulness, as evidenced by studies utilizing H1R knockout mice and pharmacological interventions. Although previous studies have reported the widespread distribution of H1R in the brains of rats, guinea pigs, monkeys, and humans, the detailed distribution in the mouse brain remains unclear. This study provides a comprehensive description of the distribution of H1R mRNA in the mouse brain using two recently developed techniques: RNAscope and in situ hybridization chain reaction, both of which offer enhanced sensitivity and resolution compared to traditional methodologies such as radioisotope labeling, which were used in previous studies. The H1R mRNA expression was observed throughout the entire brain, including key regions implicated in sleep–wake regulatory functions, such as the pedunculopontine tegmental nucleus and dorsal raphe. Additionally, strong H1R mRNA signals were identified in the paraventricular hypothalamus and ventromedial hypothalamus, which may explain the potential mechanisms underlying histamine‐mediated feeding regulation. Notably, we identified strong H1R mRNA expression in previously unreported cerebral regions, such as the dorsal endopiriform nucleus, bed nucleus of the accessory olfactory tract, and postsubiculum. These findings significantly contribute to our understanding of the multifaceted roles of H1R in diverse brain functions. [ABSTRACT FROM AUTHOR]

Dopamine neurons play crucial roles in pleasure, reward, memory, learning, and fine motor skills and their dysfunction is associated with various neuropsychiatric diseases. Dopamine receptors are the main target of treatment for neurologic and psychiatric disorders. Antipsychotics that antagonize the dopamine D2 receptor (DRD2) are used to alleviate the symptoms of these disorders but may also sometimes cause disabling side effects such as parkinsonism (catalepsy in rodents). Here we show that GPR143, a G-protein-coupled receptor for L-3,4-dihydroxyphenylalanine (L-DOPA), expressed in striatal cholinergic interneurons enhances the DRD2-mediated side effects of haloperidol, an antipsychotic agent. Haloperidol-induced catalepsy was attenuated in male Gpr143 gene-deficient (Gpr143-/y) mice compared with wild-type (Wt) mice. Reducing the endogenous release of L-DOPA and preventing interactions between GPR143 and DRD2 suppressed the haloperidol-induced catalepsy in Wt mice but not Gpr143-/y mice. The phenotypic defect in Gpr143-/y mice was mimicked in cholinergic interneuron-specific Gpr143-/y (Chat-cre;Gpr143flox/y) mice. Administration of haloperidol increased the phosphorylation of ribosomal protein S6 at Ser240/244 in the dorsolateral striatum of Wt mice but not Chat-cre;Gpr143flox/y mice. In Chinese hamster ovary cells stably expressing DRD2, co-expression of GPR143 increased cell surface expression level of DRD2, and L-DOPA application further enhanced the DRD2 surface expression. Shorter pauses in cholinergic interneuron firing activity were observed after intrastriatal stimulation in striatal slice preparations from Chat-cre; Gpr143flox/y mice compared with those from Wt mice. Together, these findings provide evidence that GPR143 regulates DRD2 function in cholinergic interneurons and may be involved in parkinsonism induced by antipsychotic drugs. [ABSTRACT FROM AUTHOR]

The relationship between mental disorders and sleep remains unclear. Two new studies show that the lateral habenula, a brain region associated with value-guided behavior, controls REM sleep and promotes emotional stability but also contributes to REM sleep disinhibition in depression. [ABSTRACT FROM AUTHOR]

Neuronal activity is modulated not only by inputs from other neurons but also by various factors, such as bioactive substances. Noradrenergic (NA) neurons in the locus coeruleus (LC-NA neurons) are involved in diverse physiological functions, including sleep/wakefulness and stress responses. Previous studies have identified various substances and receptors that modulate LC-NA neuronal activity through techniques including electrophysiology, calcium imaging, and single-cell RNA sequencing. However, many substances with unknown physiological significance have been overlooked. Here, we established an efficient screening method for identifying substances that modulate LC-NA neuronal activity through intracellular calcium ([Ca2+]i) imaging using brain slices. Using both sexes of mice, we screened 53 bioactive substances, and identified five novel substances: gastrin-releasing peptide, neuromedin U, and angiotensin II, which increase [Ca2+]i, and pancreatic polypeptide and prostaglandin D2, which decrease [Ca2+]i. Among them, neuromedin U induced the greatest response in female mice. In terms of the duration of [Ca2+]i change, we focused on prostaglandin E2 (PGE2), since it induces a long-lasting decrease in [Ca2+]i via the EP3 receptor. Conditional knock-out of the receptor in LC-NA neurons resulted in increased depression-like behavior, prolonged wakefulness in the dark period, and increased [Ca2+]i after stress exposure. Our results demonstrate the effectiveness of our screening method for identifying substances that modulate a specific neuronal population in an unbiased manner and suggest that stress-induced prostaglandin E2 can suppress LC-NA neuronal activity to moderate the behavioral response to stressors. Our screening method will contribute to uncovering previously unknown physiological functions of uncharacterized bioactive substances in specific neuronal populations. [ABSTRACT FROM AUTHOR]

Background: Insomnia is associated with psychiatric illnesses such as bipolar disorder or schizophrenia. Treating insomnia improves psychotic symptoms severity, quality of life, and functional outcomes. Patients with psychiatric disorders are often dissatisfied with the available therapeutic options for their insomnia. In contrast, positive allosteric modulation of adenosine A2A receptors (A2ARs) leads to slow-wave sleep without cardiovascular side effects in contrast to A2AR agonists. Methods: We investigated the hypnotic effects of A2AR positive allosteric modulators (PAMs) in mice with mania-like behavior produced by ablating GABAergic neurons in the ventral medial midbrain/pons area and in a mouse model of schizophrenia by knocking out of microtubule-associated protein 6. We also compared the properties of sleep induced by A2AR PAMs in mice with mania-like behavior with those induced by DORA-22, a dual orexin receptor antagonist that improves sleep in pre-clinical models, and the benzodiazepine diazepam. Results: A2AR PAMs suppress insomnia associated with mania- or schizophrenialike behaviors in mice. A2AR PAM-mediated suppression of insomnia in mice with mania-like behavior was similar to that mediated by DORA-22, and, unlike diazepam, did not result in abnormal sleep. Conclusion: A2AR allosteric modulation may represent a new therapeutic avenue for sleep disruption associated with bipolar disorder or psychosis. [ABSTRACT FROM AUTHOR]

Sleep, torpor, and hibernation are three distinct hypometabolic states. However, they have some similar physiological features, such as decreased core body temperature and slowing heart rate. In addition, the accumulation of adenosine seems to be a common feature before entry into these three states, suggesting that adenosine and its receptors, also known as P1 receptors, may mediate the initiation and maintenance of these states. This review, therefore, summarizes the current research on the roles and possible neurobiological mechanisms of adenosine and P1 receptors in sleep, torpor, and hibernation. Understanding these aspects will give us better prospects in sleep disorders, therapeutic hypothermia, and aerospace medicine. [ABSTRACT FROM AUTHOR]

Brown adipose tissue (BAT) functions as a thermogenic organ and is negatively associated with cardiometabolic diseases. N6‐methyladenosine (m6A) modulation regulates the fate of stem cells. Here, we show that the prostaglandin E2 (PGE2)–E‐prostanoid receptor 3 (EP3) axis was activated during mouse interscapular BAT development. Disruption of EP3 impaired the browning process during adipocyte differentiation from pre‐adipocytes. Brown adipocyte‐specific depletion of EP3 compromised interscapular BAT formation and aggravated high‐fat diet‐induced obesity and insulin resistance in vivo. Mechanistically, activation of EP3 stabilized the Zfp410 mRNA via WTAP‐mediated m6A modification, while knockdown of Zfp410 abolished the EP3‐induced enhancement of brown adipogenesis. EP3 prevented ubiquitin‐mediated degradation of WTAP by eliminating PKA‐mediated ERK1/2 inhibition during brown adipocyte differentiation. Ablation of WTAP in brown adipocytes abrogated the protective effect of EP3 overexpression in high‐fat diet‐fed mice. Inhibition of EP3 also retarded human embryonic stem cell differentiation into mature brown adipocytes by reducing the WTAP levels. Thus, a conserved PGE2‐EP3 axis promotes BAT development by stabilizing WTAP/Zfp410 signaling in a PKA/ERK1/2‐dependent manner. Synopsis: Development of brown adipose tissue (BAT) is tightly regulated by transcriptional and epigenetic reprogramming, but its upstream regulation remains poorly understood. Here, prostaglandin receptor signalling is shown to be a key promoter of brown adipogenesis enhancing expression of thermogenic gene programs. The PGE2/EP3 axis is activated during the development of interscapular BAT in mice.BAT‐specific depletion of EP3 results in adipocyte whitening and aggravated diet‐induced obesity.Loss of EP3 accelerates ubiquitin‐mediated degradation of N6‐methyladenosine methyltransferase WTAP, decreasing m6A‐dependent mRNA stability of brown gene transcription factor Zfp410.EP3 receptor‐mediated control of brown adipogenesis is conserved in human embryonic stem cell differentiation. [ABSTRACT FROM AUTHOR]

Background and Purpose: Modafinil is a potent eugeroic (wakefulness‐promoting) drug that is prescribed to treat narcolepsy and has a low incidence of abuse. Although previous studies have shown that modafinil‐induced arousal depends on the dopamine receptors and transporters, the specific part/s of the dopamine transmitter system underlying this mechanism remained unclear. Here, we investigated the role of mesencephalic dopamine neurons in modafinil‐evoked arousal. Experimental Approach A dopamine indicator (dLight1.1) was employed to detect dopamine changes in the nucleus accumbens (NAc) and dorsal striatum. We specifically lesioned mesencephalic dopamine neurons via diphtheria toxin (DTA) in the dopamine transporter (DAT)‐Cre mice. Then, the sleep–wake states were recorded to evaluate the effect of modafinil on arousal. Finally, the extent of DTA‐induced lesions was determined by immunohistochemistry. Key Results: Modafinil promptly increased dopamine levels in the NAc and dorsal striatum in a dose‐dependent manner. Lesioning of dopamine neurons in the substantia nigra pars compacta (SNc) or ventral tegmental area (VTA) had no significant effects on physiological sleep–wake cycles. Modafinil at 90 mg·kg−1 increased continuous wakefulness for 355 min in control mice. However, these effects were slightly decreased by 6.7% in the SNc‐lesioned mice and were prominently diminished by 32.8% in VTA‐lesioned mice. Furthermore, the modafinil‐induced arousal was completely blocked in the SNc‐VTA‐lesioned mice, whereas lesions of the dorsal raphé nucleus had no effect. Conclusion and Implications: Taken together, our findings indicate that mesencephalic dopamine neurons are essential for modafinil‐induced arousal. [ABSTRACT FROM AUTHOR]