Vasopressin facilitates excitatory transmission in slices of the rat dorso-lateral septum.
The effect of vasopressin on neurons of the rat dorso-lateral septum (DLS) was studied in brain slices with intracellular microelectrodes. Two out of 13 neurons showed a small depolarization, spontaneous activity, and increased input resistances following a 15 min exposure to 10(-6) to 10(-8) M vasopressin (VP). These membrane effects disappeared completely within 3-5 min after the application. The remaining DLS neurons treated with these vasopressin concentrations showed an increase in glutamate-mediated excitatory postsynaptic potentials (EPSPs), evoked by stimulation of the fimbria fibers. As little as 10(-12) MVP increased these EPSPs markedly in nearly 80% of the cells studied. This increase in most of the cells disappeared within 15 min after the application period, whereas the increase in EPSPs induced by 10(-10) M VP outlasted the peptide application period for more than 30 min. Neither the blockade of GABA-ergic synaptic inhibition nor the pre-treatment of the neurons with d(CH2)5-Tyr(Me)-arginine vasopressin or 2-amino-5-phosphonovaleric acid (2-APV), antagonists for the V1 type of vasopressin receptor and NMDA receptors, respectively, interfered with the EPSPs potentiating effect of the peptide. It is concluded that a type of vasopressin receptor other then the V1 type is involved in the long-lasting potentiation of the primarily non-NMDA receptor mediated transmission in DLS neurons.
Van den Hooff
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Rudolf Magnus Institute for Pharmacology, University of Utrecht, The Netherlands.
Urban
I J
IJ
D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D010852:Picrotoxin / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011945:Receptors, Angiotensin / Q000187:drug effects / Q000502:physiology*; D017483:Receptors, Vasopressin; D012686:Septal Nuclei / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects; D014667:Vasopressins / Q000494:pharmacology*
D015763:2-Amino-5-phosphonovalerate; D010852:Picrotoxin; D011945:Receptors, Angiotensin; D017483:Receptors, Vasopressin; D014667:Vasopressins