Key result
Systemic administration of angiotensin II increased excitability in 83% of vasopressin- and 75% of oxytocin-secreting neurons, an effect abolished by lesioning the subfornical organ.
The subfornical organ is an essential central nervous system structure for eliciting increases in the excitability of oxytocin- and vasopressin-secreting neurons in response to systemic angiotensin II.
Hypothesis-generating for subfornical organ mediation of angiotensin II effects in rodents; human relevance and clinical translation remain open.
Extracellular single unit recordings were obtained to investigate the effects of systemic administration of angiotensin II (ANG II) on the excitability of antidromically identified neurohypophysial neurons in the rat. Records were obtained from 89 oxytocin- or vasopressin-secreting neurons in the hypothalamic supraoptic or paraventricular nuclei. Increased excitability in response to ANG II was observed in 83% of putative vasopressin- and 75% of putative oxytocin-secreting neurons tested in intact animals. Lesion studies to identify the central nervous system site of action for such peripherally administered ANG II showed that, after electrolytic lesion of the rostral subfornical organ (SFO), neurohypophysial neurons demonstrated no increase in excitability in response to this peptide. In an attempt to correlate the synaptic events through which activation of SFO neurons may result in facilitated excitability of neurohypophysial cells, 19 cells were tested with both systemic ANG II and electrical stimulation in the SFO. These studies demonstrated that all cells which showed long-duration increases in excitability in response to electrical stimulation of SFO were also activated by systemic ANG II. It is concluded that the SFO is an essential central nervous system structure in eliciting increases in the excitability of both oxytocin- and vasopressin-secreting neurons in response to systemic ANG II. These effects may involve the activation of SFO efferents that evoke long-duration post-synaptic changes in neurohypophysial cell excitability.
No takes yet. Share an insight, caveat, or question.
Ferguson et al. (1986) studied this question. Systemic angiotensin II (ANG II) vs. Electrolytic lesion of the rostral subfornical organ (SFO) was evaluated on Excitability of antidromically identified neurohypophysial neurons. Systemic administration of angiotensin II increased excitability in 83% of vasopressin- and 75% of oxytocin-secreting neurons, an effect abolished by lesioning the subfornical organ.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: