Biology subjects

Nolte, S. S.

Publications and source records attributed to Nolte, S. S..

3 recordsLinked to original sources

bioRxiv2023

SorCS2 modulates neurovascular coupling via glutamatergic and calcium signaling in astrocytes

AO_SCPLOWBSTRACTC_SCPLOWSorCS2 is involved in trafficking of membrane receptors and transporters. SorCS2 is implicated in brain disorders, but the mechanism remains uncertain. We hypothesized that SorCS2 expression is important for neurovascular coupling. Brains from P8 and 2-month-old wild type mice were stained for SorCS2 and compared to SorCS2 knockouts (Sorcs2-/-). Changes in cerebral perfusion in response to sensory stimulation, i.e., neurovascular coupling, were compared in vivo. Neurovascular coupling was also assessed ex vivo in brain slices loaded with calcium-sensitive dye. Proteomics of astrocytes was analyzed for ingenuity pathways. SorCS2 was strongly expressed in astrocytic endfeet of P8 mice but only in few astrocytes from 2-month-old brains. Sorcs2-/- mice demonstrated reduced neurovascular coupling. This was associated with reduced astrocytic calcium response to neuronal excitation in Sorcs2-/- mice. No difference in cerebral artery caliber nor in endothelial function was seen between wild type and Sorcs2-/- mice. Proteomics indicated reduced glutamatergic signaling and suppressed calcium signaling in Sorcs2-/- astrocytes. We suggest that SorCS2 expression is important for neurovascular coupling due to modulation of glutamatergic and calcium signaling in astrocytes.

neuroscience↗

bioRxiv2023

GABAergic signaling shapes multiple aspects of Drosophila courtship motor behavior

Inhibitory neurons are essential for nervous system function. GABA is the most important neurotransmitter for fast neuronal inhibition in vertebrates and invertebrates. GABAergic signaling in sex specific, fruitless expressing neuronal circuits of Drosophila is required for multiple aspects of male courtship behavior. RNAi mediated knockdown of the GABA producing enzyme Gad1 and the ionotropic receptor Rdl in the ventral nerve cord causes uncoordinated and futile copulation attempts, defects in wing extension choice and severe alterations of courtship song. Altered song of GABA depleted males fails to stimulate female receptivity, but rescue of song patterning alone is not sufficient to rescue male mating success. Knockdown of Gad1 and Rdl in brain circuits abolishes courtship conditioning. We characterize the around 220 neurons coexpressing Gad1 and Fruitless in the Drosophila male nervous system and propose inhibitory circuit motifs underlying key features of courtship behavior based on the observed phenotypes.

neuroscience↗

bioRxiv2020

Synapse-specific direction selectivity in retinal bipolar cell axon terminals

The ability to encode the direction of image motion is fundamental to our sense of vision. Direction selectivity along the four cardinal directions is thought to originate in direction-selective ganglion cells (DSGCs), due to directionally-tuned GABAergic suppression by starburst cells. Here, by utilizing two-photon glutamate imaging to measure synaptic release, we reveal that direction selectivity along all four directions arises earlier than expected, at bipolar cell outputs. Thus, DSGCs receive directionally-aligned glutamatergic inputs from bipolar cell boutons. We further show that this bouton-specific tuning relies on cholinergic excitation and GABAergic inhibition from starburst cells. In this way, starburst cells are able to refine directional tuning in the excitatory visual pathway by modulating the activity of DSGC dendrites and their axonal inputs using two different neurotransmitters.

neuroscience↗