The type 1 corticotropin-releasing hormone receptor (CRH-R1) influences biological responses important for adaptation to stressful stimuli, through activation of multiple downstream effectors. The structural motifs within CRH-R1 that mediate G protein activation and signaling selectivity are unknown. The aim of this study was to gain insights about important structural determinants within the third intracellular loop (IC3) of the human CRH-R1α important for cAMP and ERK1/2 pathways activation and selectivity. We investigated the role of the juxtamembrane regions of IC3 by mutating amino acid cassettes or specific residues to alanine. Although simultaneous tandem alanine mutations of both juxtamembrane regions Arg²⁹²-Met²⁹⁵ and Lys³¹¹-Lys³¹⁴ reduced ligand binding and impaired signaling, all other mutant receptors retained high affinity binding, indistinguishable from wild-type receptor. Agonist-activated receptors with tandem mutations at the proximal or distal terminal segments enhanced activation of adenylyl cyclase by 50–75% and diminished activation of inositol trisphosphate and ERK1/2 by 60–80%. Single Ala mutations identified Arg²⁹², Lys²⁹⁷, Arg³¹⁰, Lys³¹¹, and Lys³¹⁴ as important residues for the enhanced activation of adenylyl cyclase, partly due to reduced inhibition of adenylyl cyclase activity by pertussis toxin-sensitive G proteins. In contrast, mutation of Arg²⁹⁹ reduced receptor signaling activity and cAMP response. Basic as well as aliphatic amino acids within both juxtamembrane regions were identified as important for ERK1/2 phosphorylation through activation of pertussis toxin-sensitive G proteins as well as G_q proteins. These data uncovered unexpected roles for key amino acids within the highly conserved hydrophobic N- and C-terminal microdomains of IC3 in the coordination of CRH-R1 signaling activity.

Abnormal sleep architecture and white matter hyperintensities (WMHs) may be involved in cognitive impairment. There is little evidence on the connections between WMHs and chronic insomnia disorder (CID). Therefore, we evaluated the severity of WMHs and polysomnography parameters as well as cognitive tests to explore the underlying connections. There was no significant difference in sex, age, or educational attainment (years) between the two groups. The data showed significant decreases in total sleep time, sleep efficiency, and percentage of time spent in stage nonrapid eye movement sleep 3 in the CID group, but this group also showed prolonged sleep latency and increased percentages of time spent in stages nonrapid eye movement sleep 1 and nonrapid eye movement sleep 2 and wake after sleep onset. Moreover, chronic insomniacs showed poor performance on the attention, intelligence, and memory tests, as well as visual recognition and visual regeneration. Importantly, WMHs were observed to be associated with sleep latency, percentage of time spent in stage nonrapid eye movement sleep 1, and percentage of time spent in stage nonrapid eye movement sleep 3. In conclusion, our findings suggest that there are certain underlying correlations between WMHs and sleep architecture. Abnormal sleep architecture and WMHs could be involved in the impairment of cognitive function in CID. However, it remains unclear whether WMHs are a pre-existing abnormality or a consequence of CID.

Objective: The aim of this study was to investigate the correlation between sleep chronotype and metabolic markers to further reveal the influence of sleep chronotype on human health.Methods: The Morningness-Eveningness Questionnaire was administered to 442 volunteers aged 23–70 years old. The sleep chronotype was divided into morning type (167 cases), neither type (224 cases), and evening type (51 cases). Blood pressure was recorded, and fasting venous blood samples were collected to assess liver function, renal function, blood glucose levels, blood lipid profile, and other biochemical parameters.Results: 1. There was a statistically significant difference in the age of the morning type, neither type, and evening type (p < 0.01), but there was no significant difference in gender, height, weight, and BMI (ps > 0.05). 2. After controlling for the influence of age-related factors, significant differences were seen between morning type, neither type, and evening type groups in creatinine and aspartate aminotransferase (p < 0.05). 3. After controlling for the influence of age-related factors, the evening type group had lower systolic blood pressure, diastolic pressure, and mean arterial pressure (MAP) compared to the morning type and neither type (p < 0.05). 4. After controlling the influence of age-related factors, the MEQ scores were positively correlated with systolic blood pressure, diastolic blood pressure, and mean arterial pressure (r = 0.099, 0.096, 0.104, ps < 0.05).Conclusion: The evening sleep type is more prone to daytime sleepiness. There were significant differences observed in systolic blood pressure, diastolic blood pressure, and MAP. These variations may be linked to the effects of different sleep chronotype on blood pressure regulation or the blood pressure’s autonomous rhythm.