Projection-defined median raphe Pet+ subpopulations are diversely implicated in seizure.

The raphe nuclei, the primary resource of forebrain 5-HT, play an important but heterogeneous role in regulating subcortical excitabilities. Fundamental circuit organizations of different median raphe (MR) subsystems are far from completely understood. In the present study, using cell-specific viral tracing, Ca2+ fiber photometry and epilepsy model, we map out the forebrain efferent and afferent of different MR Pet+ subpopulations and their divergent roles in epilepsy. We found that PetMR neurons send both collateral and parallel innervations to different downstream regions through different subpopulations. Notably, CA3-projecting PetMR subpopulations are largely distinct from habenula (Hb)-projecting PetMR subpopulations in anatomical distribution and topological organization, while majority of the CA3-projecting PetMR subpopulations are overlapped with the medial septum (MS)-projecting PetMR subpopulations. Further, using Ca2+ fiber photometry, we monitor activities of PetMR neurons in hippocampal-kindling seizure, a classical epilepsy model with pathological mechanisms caused by excitation-inhibition imbalance. We found that soma activities of PetMR neurons are heterogeneous during different periods of generalized seizures. These divergent activities are contributed by different projection-defined PetMR subpopulations, manifesting as increased activities in CA3 but decreased activity in Hb resulting from their upstream differences. Together, our findings provide a novel framework of MR subsystems showing that projection-defined MR Pet+ subpopulations are topologically heterogenous with divergent circuit connections and are diversely implicated in seizures. This may help in the understanding of heterogeneous nature of MR 5-HTergic subsystems and the paradox roles of 5-HTergic systems in epilepsy.

The diverse role of the raphe 5-HTergic systems in epilepsy.

The raphe nuclei comprise nearly all of 5-hydroxytryptaminergic (5-HTergic) neurons in the brain and are widely acknowledged to participate in the modulation of neural excitability. "Excitability-inhibition imbalance" results in a variety of brain disorders, including epilepsy. Epilepsy is a common neurological disorder characterized by hypersynchronous epileptic seizures accompanied by many psychological, social, cognitive consequences. Current antiepileptic drugs and other therapeutics are not ideal to control epilepsy and its comorbidities. Cumulative evidence suggests that the raphe nuclei and 5-HTergic system play an important role in epilepsy and epilepsy-associated comorbidities. Seizure activities propagate to the raphe nuclei and induce various alterations in different subregions of the raphe nuclei at the cellular and molecular levels. Intervention of the activity of raphe nuclei and raphe 5-HTergic system with pharmacological or genetic approaches, deep brain stimulation or optogenetics produces indeed diverse and even contradictory effects on seizure and epilepsy-associated comorbidities in different epilepsy models. Nevertheless, there are still many open questions left, especially regarding to the relationship between 5-HTergic neural circuit and epilepsy. Understanding of 5-HTergic network in a circuit- and molecule-specific way may not only be therapeutically relevant for increasing the drug specificity and precise treatment in epilepsy, but also provide critical hints for other brain disorders with abnormal neural excitability. In this review we focus on the roles of the raphe 5-HTergic system in epilepsy and epilepsy-associated comorbidities. Besides, further perspectives about the complexity and diversity of the raphe nuclei in epilepsy are also addressed.

The complete chloroplast genome sequence of Rubus hirsutus Thunb. and a comparative analysis within Rubus species.

Rubus hirsutus is a type of tonifying kidney-essence herb that belongs to the Rosaceae family, and has been commonly used to treat multiple diseases, such as polyuria, impotence, and infertility. In this study, we determined the complete chloroplast sequence of R. hirsutus and conduced a comparative analysis within the genus Rubus. The assembled chloroplast (cp.) genome is 156,380 bp in length with a GC content of 37.0% and shares a conserved quadripartite structure within the other cp. genomes in this genus. A total of 132 unique genes were annotated in the cp. genome of R. hirsutus, which contained 87 protein-coding genes, 37 tRNAs, and eight rRNAs. Seventeen duplicated genes were identified in the inverted repeats region. Furthermore, 70 simple sequence repeats and 35 long repeats were detected in total in the R. hirsutus chloroplast genome. Eight mutational hotspots were identified in the cp. genome of this species with higher nucleotide variations in non-coding regions than those of coding regions. Furthermore, the gene order, codon usage, and repeat sequence distribution were highly consistent in Rubus according to the results of a comparative analysis. A phylogenetic analysis indicated that there was a sister relationship between R. hirsutus and R. chingii. Overall, the complete chloroplast genome of R. hirsutus and the comparative analysis will help to further the evolutionary study, conservation, phylogenetic reconstruction, and development of molecular barcodes for the genus Rubus.

Paradoxical effects of posterior intralaminar thalamic calretinin neurons on hippocampal seizure via distinct downstream circuits.

Epilepsy is a circuit-level brain disorder characterized by hyperexcitatory seizures with unclear mechanisms. Here, we investigated the causal roles of calretinin (CR) neurons in the posterior intralaminar thalamic nucleus (PIL) in hippocampal seizures. Using c-fos mapping and calcium fiber photometry, we found that PIL CR neurons were activated during hippocampal seizures in a kindling model. Optogenetic activation of PIL CR neurons accelerated seizure development, whereas inhibition retarded seizure development. Further, viral-based circuit tracing verified that PIL CR neurons were long-range glutamatergic neurons, projecting toward various downstream regions. Interestingly, selective inhibition of PIL-lateral amygdala CR circuit attenuated seizure progression, whereas inhibition of PIL-zona incerta CR circuit presented an opposite effect. These results indicated that CR neurons in the PIL play separate roles in hippocampal seizures via distinct downstream circuits, which complements the pathogenic mechanisms of epilepsy and provides new insight for the precise medicine of epilepsy.

Molecular structure and phylogenetic analysis of complete chloroplast genomes of medicinal species Paeonia lactiflora from Zhejiang Province.

Paeonia lactiflora is a geo-authentic and superior medicinal plant in Zhejiang province. Here, we report the complete chloroplast genome sequence of P. lactiflora. The total genome size of P. lactiflora is 153,405 bp in length, including a small single-copy (SSC) region of 16,969 bp, a large single-copy (LSC) region of 84,340 bp separated by a pair of inverted repeats (IRs) of 26,048 bp. The overall annotated gene number is 109, containing 76 protein-coding genes, 29 tRNAs and 4 rRNAs. The entire GC content of P. lactiflora is 38.43%, with the highest GC content of 42.99% in IR region. A total of 52 simple sequence repeats are identified in the cp genome of P. lactiflora. Phylogenetic analysis indicated a sister relationship between P. lactiflora and P. veitchii, and supported a unique evolutionary status of Family Paeoniaceae. This work provides a valuable genetic resource to develop robust markers and investigate the population genetics diversities for this famous medicinal species.