Electrophysiological evidence for oxytocin receptors on sympathetic preganglionic neurones--an in vitro study on the neonatal rat.

The action of oxytocin (0.01-1 microM) on sympathetic preganglionic neurones was studied by intracellular recording in slices of neonatal rat thoracic spinal cord. In 85% of the cells superfusion induced a slow tetrodotoxin-insensitive depolarization accompanied by the appearance or increase in frequency of repetitive discharges.

Localization of oxytocin binding sites in the thoracic and upper lumbar spinal cord of the adult and postnatal rat: a histoautoradiographic study.

Oxytocin binding sites were detected by autoradiography on films and emulsion-coated sections in the spinal cord of adult and postnatal rats from C8 to L2, using a highly selective 125I-labelled oxytocin antagonist. Oxytocin binding sites were detected on all transverse sections in the dorsal horn, where labelling was scattered over laminae I and II. The autonomic areas, i.

Caffeine-induced Ca2+ release inhibits GABAA responsiveness in rat identified native primary afferents.

It has been shown previously that an increase in cytoplasmic Ca2+ concentration depresses the GABA-A response. However, little attention has been paid to the Ca2+ source involved. In the present study, we show that the Ca2+ increase triggered by caffeine-induced Ca2+ release from the intracellular pool inhibits the GABA-A response, whereas Ca2+ influx through voltage-activated Ca2+ channels has no effect on this response.

Synthesis and biochemical evaluation of baclofen analogues locked in the baclofen solid-state conformation.

The synthesis of six close analogues of baclofen [3-(4-chlorophenyl)-4-aminobutyric acid] (BAC), a potent GABAB agonist, are reported. The compounds were designed starting from the structural informations contained in the solid state of BAC, regarded as a possible bioactive conformation, in which the p-chlorophenyl ring is perpendicular to the GABA backbone. A similar conformational situation was created by rigidifying the BAC structure by means of methylene (1), ethylene (2 and 6), or propylene (3) units, or by introducing chlorine atoms (4 and 5) into the ortho positions ("ortho effect").

Quantitative evaluation of the properties of a pyridazinyl GABA derivative (SR 95531) as a GABAA competitive antagonist. An electrophysiological approach.

We have investigated the effects of an aryl-aminopyridazine derivative of GABA (SR 95531) on dose-response curves of GABA-induced depolarizations from dorsal root ganglion neurones recorded intracellularly. The reversible shift to the right of the dose-response curves in a parallel fashion and the dissociation constant (KB) value of 0.13 +/- 0.