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Sikdar, S. K.

Publications and source records attributed to Sikdar, S. K..

2 recordsLinked to original sources

Semiconducting carbon nanotubes decrease neuronal bursting in a network of rat hippocampal neurons in vitro while increasing intrinsic excitability of single neurons

The diverse electrical, chemical and structural properties of the functional derivatives of carbon nanotubes (CNTs) have shown biomedical possibilities for neuroprosthesis or neural interfaces. However, the studies have been generally confined to metallic CNTs that affect cell viability unless chemically functionalized for biocompatibility. Here, we explored the effects of semiconducting single-walled carbon nanotubes (ssw-CNT), on the active electrical properties of dissociated hippocampal neurons in-vitro using multielectrode array, calcium imaging and whole-cell patch clamp recordings. The findings show that ssw-CNT treatment regulates neural network excitability from burst to tonic firing by changing the calcium dynamics. However, at a single neuronal level, ssw-CNT increases neuronal excitability.

neuroscience↗

Structural insights into pore dynamics of human Pannexin isoforms

Pannexins are single-membrane large-pore ion channels that release ATP upon activation. Three isoforms of pannexins, 1, 2, and 3, perform diverse cellular roles, including inflammation, differentiation, neuropathic pain, and ATP release. In this study, we report the cryoEM structure of pannexin 3 at 3.9 [A] and characterize the structural differences with pannexin isoforms 1 and 2. We observe the organization of the Pannexin 3 vestibule into two distinct chambers with a wider pore radius in comparison to both PANX1 and 2 isoforms. We further report the structure of pannexin1 congenital mutant R217H in the resolution range of 3.9 [A]. The congenital mutant R217H in transmembrane helix3 (TM3), R217H induce structural changes that leads to a partially closed pore and altered ATP interaction propensities. The channel conductance of the congenital mutant displays weakened voltage sensitivity. The results showcase a complete comparison of the three pannexin isoform structures that along with the structure of Pannexin 1 congenital mutant highlight distinct structural features of pannexin isoforms and the allosteric role of distant substitutions in dictating channel behavior in Pannexin 1.

biochemistry↗