Central and peripheral release of vasopressin and oxytocin in the conscious rat after osmotic stimulation.
Vasopressin (AVP) and oxytocin (OXT) were measured by radioimmunoassay in push-pull perfusates and tissue samples of various brain areas, plasma and cerebrospinal fluid (CSF) of male rats in response to osmotic stimulation. Hypertonic saline caused a significant rise in plasma AVP and OXT and different changes in peptide contents, in the septum and hippocampus at 30 and 60 min after intraperitoneal injection. Push-pull perfusion (20 microliters artificial CSF/min, 30-min periods) of the septum and dorsal hippocampus of conscious, unrestrained animals revealed a significant, stimulus-evoked release of both AVP and OXT. This release was: (1) not always reflected by corresponding changes in the regional peptide content; (2) simultaneous with the peripheral release from the posterior pituitary; and (3) probably the result of synaptic/parasynaptic events as suggested by use of agents in the artificial CSF which either inhibit or facilitate the release from intact fibre terminals.
Landgraf
R
R
Department of Cell Biology and Regulation, Karl Marx University, Leipzig, G.D.R.
Neumann
I
I
Schwarzberg
H
H
D000818:Animals; D001923:Brain Chemistry; D008297:Male; D009995:Osmosis; D010121:Oxytocin / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism; D011863:Radioimmunoassay; D051381:Rats; D011919:Rats, Inbred Strains; D014667:Vasopressins / Q000032:analysis* / Q000097:blood / Q000134:cerebrospinal fluid / Q000378:metabolism
D014667:Vasopressins; D010121:Oxytocin