2026-10-13T19:30:56Z https://api.figshare.com/v2/oai

oai:figshare.com:article/34036001 2026-09-30T17:42:52Z category_7 category_12 category_15 category_16 category_873 category_106 category_734 portal_5 item_type_1 month_year_09_2026

Single neuron and homogeneous population basal activity and prolonged osmotic challenge and recovery. Duncan J. MacGregor (25145402) Medicine Cell Biology Neuroscience Physiology Chemical Sciences not elsewhere classified Science Policy Biological Sciences not elsewhere classified regulate water loss dynamically heterogeneous patterns complete neural system neuronal cell bodies prolonged osmotic challenge peptide hormone vasopressin hypothalamic vasopressin neurons extracellular fluid osmolarity distributed neuroendocrine system stores gradually decline distant hormone stores detailed neuronal model despite upregulated synthesis turn trigger secretion regulate plasma volume maintain hormone supply div >< p 2 +</ sup modelling vasopressin synthesis synthesis dynamics based activity dependent upregulation plasma volume dependent upregulation sustained challenge storage dynamics recovery based neuroendocrine cells model suggests elevated osmolarity neuronal activity large stores coordinate synthesis timescale memory slow recovery several days salt loading posterior pituitary pituitary terminals physiological input mrna content mrna acts intracellular ca homeostatic systems generate complex form part experimentally tested demand balance coupling spiking axonal terminals The plots on the left show basal activity sustaining a mean 1pg/ml plasma vasopressin. The transcription rate rapidly rises to sustain mRNA content at 15 units. With default synthesis rate scaling sr = 1.1, the synthesis rate slightly exceeds the secretion rate and the reserve store increases (blue). Setting sr = 0.65 (green) maintains a stable store. Removing synthesis by setting sr = 0 (red) shows a depleting store. The plots on the right show a 5 day osmotic challenge (a linear ramp from basal, simulating progressive dehydration or salt loading) followed by 10 day recovery (input returned to basal). The transcription rate mostly tracks the osmotic stimulus with some drop off due to non-linearities in the spiking response. The mRNA content rises non-linearly as the balance shifts between transcription, and depletion due to synthesis (translation). The synthesis rate increases but fails to track the increasing secretion rate. The reserve store is gradually depleted to ~27%. Plasma vasopressin increases initially linearly but then slows as the neurons shift from phasic to continuous spiking. Following the ramped challenge, secretion falls to basal rates, but elevated synthesis is sustained by the increased mRNA content, depleting this to recharge the reserve store. A 100 neuron homogeneous population produces the same response with less noise. 2026-09-30T17:55:49Z Image Figure 10.1371/journal.pcbi.1014832.g004 https://figshare.com/articles/figure/_p_Single_neuron_and_homogeneous_population_basal_activity_and_prolonged_osmotic_challenge_and_recovery_p_/34036001 CC BY 4.0