Abstract
The aim of this study was to investigate effects of oxytocin (OT) on electrical neuronal activities in rat subfornical organ (SFO) and compare its action with the well-described excitatory effects of blood-borne angiotensin II (ANG II) on the same SFO neurons. With the use of extracellular recordings from spontaneously active neurons in slice preparations of the SFO of male rats, 11.7% of tested neurons (n = 206) were excited and 9.7% were inhibited by superfusion with 10-6 M OT. Both excitatory and inhibitory effects of OT were dose dependent with similar threshold concentrations and were blocked by a specific OT-receptor antagonist but not by a vasopressin receptor antagonist. Blocking synaptic transmission with low calcium medium suppressed only inhibitory effects of OT. All but one of the OT-sensitive neurons were also excited by superfusion with ANG II at a concentration much lower than required for OT, suggesting that synaptically released OT rather than blood- borne OT alters the activity of SFO neurons in vivo. The results support the hypothesis that neurally released OT may modulate SFO-mediated functions by acting on OT-sensitive neurons.
| Original language | English |
|---|---|
| Pages (from-to) | E1004-E1008 |
| Journal | American Journal of Physiology - Endocrinology and Metabolism |
| Volume | 276 |
| Issue number | 6 39-6 |
| DOIs | |
| Publication status | Published - 1999 Jun |
| Externally published | Yes |
Keywords
- Angiotensin II
- Extracellular recording
- Osmoregulation
- Vasopressin
ASJC Scopus subject areas
- Endocrinology, Diabetes and Metabolism
- Physiology
- Physiology (medical)
