Glutamatergic neurons in ventral pallidum modulate heroin addiction via epithalamic innervation in rats.

Glutamatergic neurons in ventral pallidum (VPGlu) were recently reported to mediate motivational and emotional behavior, but its role in opioid addiction still remains to be elucidated. In this study we investigated the function of VPGlu in the context-dependent heroin taking and seeking behavior in male rats under the ABA renewal paradigm. By use of cell-type-specific fiber photometry, we showed that the calcium activity of VPGlu were inhibited during heroin self-administration and context-induced relapse, but activated after extinction in a new context. The drug seeking behavior was accompanied by the decreased calcium signal of VPGlu. Chemogenetic manipulation of VPGlu bidirectionally regulated heroin taking and seeking behavior. Anterograde tracing showed that the lateral habenula, one of the epithalamic structures, was the major output region of VPGlu, and its neuronal activity was consistent with VPGlu in different phases of heroin addiction and contributed to the motivation for heroin. VPGlu axon terminals in LHb exhibited dynamic activity in different phases of heroin addiction. Activation of VPGlu-LHb circuit reduced heroin seeking behavior during context-induced relapse. Furthermore, the balance of excitation/inhibition from VP to LHb was shifted to enhanced glutamate transmission after extinction of heroin seeking motivation. Overall, the present study demonstrated that the activity of VPGlu was involved in the regulation of heroin addiction and identified the VPGlu-LHb pathway as a potential intervention to reduce heroin seeking motivation.

Single-cell transcriptome analyses reveal critical regulators of spermatogonial stem cell fate transitions.

BACKGROUND: Spermatogonial stem cells (SSCs) are the foundation cells for continual spermatogenesis and germline regeneration in mammals. SSC activities reside in the undifferentiated spermatogonial population, and currently, the molecular identities of SSCs and their committed progenitors remain unclear. RESULTS: We performed single-cell transcriptome analysis on isolated undifferentiated spermatogonia from mice to decipher the molecular signatures of SSC fate transitions. Through comprehensive analysis, we delineated the developmental trajectory and identified candidate transcription factors (TFs) involved in the fate transitions of SSCs and their progenitors in distinct states. Specifically, we characterized the Asingle spermatogonial subtype marked by the expression of Eomes. Eomes+ cells contained enriched transplantable SSCs, and more than 90% of the cells remained in the quiescent state. Conditional deletion of Eomes in the germline did not impact steady-state spermatogenesis but enhanced SSC regeneration. Forced expression of Eomes in spermatogenic cells disrupted spermatogenesis mainly by affecting the cell cycle progression of undifferentiated spermatogonia. After injury, Eomes+ cells re-enter the cell cycle and divide to expand the SSC pool. Eomes+ cells consisted of 7 different subsets of cells at single-cell resolution, and genes enriched in glycolysis/gluconeogenesis and the PI3/Akt signaling pathway participated in the SSC regeneration process. CONCLUSIONS: In this study, we explored the molecular characteristics and critical regulators of subpopulations of undifferentiated spermatogonia. The findings of the present study described a quiescent SSC subpopulation, Eomes+ spermatogonia, and provided a dynamic transcriptional map of SSC fate determination.

Hedscandines A-C, three undescribed indole alkaloids from Hedyotis scandens with their anti-MRSA activity.

Hedscandines A-C (1-3), three undescribed indole alkaloids were isolated from Hedyotis scandens Roxb, a traditional Chinese medicine widely used in the treatment of respiratory ailments. Their structures were elucidated by extensive spectroscopic data and electronic circular dichroism calculation. Hedscandine A (1), possessed a unique carbon skeleton with a 1,4-oxazonin-2(3H)-one core system and displayed a rapid bactericidal activity against MRSA with a MIC value of 16 µg/mL. Mechanistic studies showed that compound 1 could disrupt the integrity of bacterial cell membranes and thus lead to bacterial death.

[Chemical constituents from whole herb of Hedyotis scandens].

This study aimed to investigate the chemical constituents in the water extract of the whole herb of Hedyotis scandens by silica gel, ODS, and MCI column chromatographies together with preparative high-performance liquid chromatography(HPLC). The structures of isolated constituents were identified by NMR, HR-ESI-MS, etc. Thirteen compounds were isolated and identified as methyl 4-benzoyloxy-3-methoxybenzeneacetate(1), 4-benzoyloxy-3-methoxybenzeneacetic acid(2), 3-(4-hydroxy-3-methoxyphenyl)-propanoic acid(3), salicylic acid(4), 3-hydroxy-4-methoxypyridine(5), syringic acid(6), hydroxycinnamic acid(7),(R)-6-methyl-4,6-bis(4-methylpent-3-enyl)cyclohexa-1,3-dienecarbaldehyde(8), 1,2-bis(4-hydroxy-3-methoxyphenyl)-1,3-propanediol(9), 1H-indole-3-carboxaldehyde(10), isoscopoletin(11), syringaresinol(12), and pinoresinol(13). Among them, compounds 1 and 2 were new phenolic acid compounds, compounds 3-5, 8-11, and 13 were isolated from this genus for the first time, and compounds 6, 7, and 12 were obtained from H. scandens for the first time. The activity test showed that compounds 1 and 10 had a certain inhibitory effect on Mycobacterium smegmatis, with MIC_(50) values of 58.5 and 33.3 µg·mL~(-1), respectively.