Neurones in the supraoptic nucleus of the rat are regulated by a projection from the suprachiasmatic nucleus

Abstract

In the rat, projections from the suprachiasmatic nucleus (SCN) to the supraoptic nucleus (SON) of the hypothalamus were characterized in vivo using extracellular recordings and in slice preparations using both extracellular and whole‐cell patch clamp recording. Of 117 magnocellular neurones recorded in the SON in vivo, fifteen (13%) displayed a short latency excitation, sixty‐eight (58%) a short latency inhibition, six (5%) were unresponsive and twenty‐eight (24%) gave long latency responses following SON stimulation. The responses of putative vasopressin cells in the SON to SCN stimulation in vivo (4 out of 61 cells, 7% excited; 49 out of 61 cells, 80% inhibited) were significantly different from those of putative oxytocin cells (10 out of 50 cells, 20% excited and 16 out of 50 cells, 32% inhibited; P < 0.02, test for differences between proportions). Recordings in vitro using patch technology in whole‐cell mode showed both inward and outward currents in SON cells at holding potentials near resting membrane potential following stimulation of the SCN region. The outward currents could be blocked by bicuculline (10 μm; n= 7) and the inward currents were blocked by the non‐NMDA antagonist 6‐nitro‐7‐sulphamoylbenzo(f)quinoxaline‐2,3‐dione (5 μm; n= 4). We conclude that there is a strong projection from the SCN to the SON with both inhibitory (GABAergic) and excitatory (glutamatergic) components which may regulate the daily changes in neurohypophysial hormone secretion.

Rola błonowych receptorów melatoniny w zależnym od melatoniny uwalnianiu oksytocyny z układu podwzgórze-część nerwowa przysadki szczura — badania in vitro oraz in vivo

“…intact axons of the oxytocinergic neurons), also the SCN, where strong MT 1 receptor expression has been discovered in many species [17][18]20]. Thanks to direct neuronal projection from the SCN to the PVN [38] and SON [39], some of the SCN neurons could, therefore, integrate the afferent signals derived from melatonin via its MT 1 receptor and thereafter transmit them directly to oxytocinergic neurons in the SON and/or PVN.…”

Pharmacological Imposition of Sleep Slows Cognitive Decline and Reverses Dysregulation of Circadian Gene Expression in a Transgenic Mouse Model of Huntington's Disease

“…The brains were excised and cooled in ice-cold, oxygenated artificial CSF (aCSF). The composition of the aCSF was as follows (in mM): 124 NaCl, 3 KCl, 1.24 KH 2 PO 4 , 2.1 CaCl 2 , 1.3 MgSO 4 , 24 NaHCO 3 , and 10 glucose (Cui et al, 1997). Sagittal hypothalamic slices (500 m) containing the suprachiasmatic nucleus were cut on a vibratome (Series 1000; Horwell Instruments, St. Louis, MO).…”

Adenovirus-Mediated Gene Delivery to Hypothalamic Magnocellular Neurons in Mice

“…2,4 The contribution of magnocellular hypothalamic neurons located in the supraoptic (SON) and paraventricular (PVN) nuclei in the control of body fluid and cardiovascular homeostasis has been described. [5][6][7][8][9][10] The soma of magnocellular neurons in hypothalamic SON and PVN synthesizes the neurohormone vasopressin. Axons from these cells project to the neurohypophysis (NH), where this peptide is stored in nerve terminals for release into the peripheral circulation.…”