Phosphatidic acid activation of protein kinase C in LA-N-1 neuroblastoma cells.

Phosphatidic acid (PA), a hydrolytic product of phospholipase D activity, stimulated cytosolic protein kinase C (PKC) activity when LA-N-1 neuroblastoma cells in culture were treated with PA, without translocating the enzyme to the membrane. Treatment of cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) translocated and activated PKC in a dogmatic manner. Partially purified PKC activity derived from LA-N-1 neuroblastoma cells was stimulated by PA alone or in the presence of phosphatidylserine or TPA, without affecting [3H]phorbol dibutyrate binding, indicating that the site of action of PA was different from the phorbol ester or diacylglycerol binding site.

Cytoplasmic poly(ADP-ribose)polymerase from mouse plasmacytoma free messenger ribonucleoprotein particles: purification and characterization.

A cytoplasmic poly(ADP-ribose)polymerase (PARP) was purified from mouse plasmacytoma free messenger ribonucleoprotein particles using chromatography on 3-aminobenzamide affigel-10. The purified protein showed one band at 116 kDa on SDS-polyacrylamide gel electrophoresis and shared similar antigenic sites to the nuclear PARP. An apparent Km for NAD of 100.

Evidence for state-dependent retrieval in conditioned place aversion.

State-dependent retrieval (SDR) in conditioned place aversion (CPA) was observed using Long-Evans male rats, with three different aversive drugs injected ip: lithium chloride (31.8 mg/kg), FG 7142 (10 mg/kg), and naloxone (5 mg/kg). Experiment 1 showed that state-dependent dissociation was complete with lithium chloride following two conditioning trials, but disappeared when the number of learning sessions was increased.

A unique hydrophobic domain of rat brain globular acetylcholinesterase for binding to cell membranes.

Both salt-soluble and detergent-soluble rat brain globular acetylcholinesterases (SS- and DS- AChE EC 3.1.1.

Developmental changes of EAA metabotropic receptor activity in rat cerebellum.

The potency but not the efficacy of t-ACPD stimulation of phosphatydil inositide hydrolysis changes in developing rat cerebellum. This suggests that the excitatory amino-acid-stimulated metabotropic receptors and/or their coupling are ontogenically regulated. In this, cerebellum differs from other CNS regions where only efficacy changes were described.

N-methyl-D-aspartate antagonists suppress the development of frog symmetric monocular optokynetic nystagmus observed after unilateral visual deprivation.

In monocular vision, frogs display a unidirectional optokinetic nystagmus (OKN), reacting only to temporal-nasal (T-N) stimulation. The OKN N-T component is almost absent. However, prolonged monocular visual deprivation by unilateral eyelid suture provoked the appearance of the N-T component.

Wild running elicited by microinjections of bicuculline or morphine into the inferior colliculus of rats: lack of effect of periaqueductal gray lesions.

Bicuculline methiodide, a GABAA receptor antagonist, or a high dose of morphine was injected at the same site within the inferior colliculus (IC) of rats. Both drugs elicited the same behavioral activity (wild running). However, the time course and magnitude of the effects of the two drugs differed.

Conditioned place preference induced by Ro 16-6028, a benzodiazepine receptor partial agonist.

A place conditioning situation was used to assess the putative affective properties of benzodiazepine receptor ligands in the rat. The benzodiazepine receptor partial agonist Ro 16-6028 induced a conditioned place preference, suggesting that this compound has rewarding properties. The benzodiazepine receptor antagonist Ro 15-1788 induced neither place preference nor aversion, but prevented the place preference induced by Ro 16-6028, suggesting that the rewarding effects of Ro 16-6028 are due to its action on the benzodiazepine receptor.

Plasticity of the frog monocular OKN: involvement of pretectal GABAergic and cholinergic systems.

The frog horizontal monocular optokinetic nystagmus (OKN) is asymmetrical, the temporal-nasal (T-N) stimulation being the sole stimulation efficient to evoke the reflex, the nasal-temporal (N-T) component being almost absent. Coil recordings showed that, in adult animals, prolonged monocular visual deprivation by unilateral eyelid suture provoked the appearance of the N-T component. The OKN became symmetrical, reacting for both directions of stimulation.

C-fos immunoreactivity in the brain following unilateral electrical stimulation of the dorsal periaqueductal gray in freely moving rats.

C-fos immunoreactivity was used to reveal brain areas in which neurons were influenced by electrical stimulations applied to the dorsal periaqueductal gray. These stimulations were applied in freely moving rats so that the resulting behaviors could be observed. Shortly afterwards, the brains of the rats were processed for C-fos immunoreactivity.

The pretectal cholinergic system is involved through two opposite ways in frog monocular OKN asymmetry.

Frog monocular horizontal optokinetic nystagmus (OKN) has been studied by coil recordings, before and after unilateral microinjection of cholinergic drugs into the pretectum. The recorded eye was either contralateral or ipsilateral to the injected structure. Before injection, monocular OKN displayed a directional asymmetry, reacting only to stimulations in the temporonasal (T-N) direction.

Involvement of intrathalamic GABAB neurotransmission in the control of absence seizures in the rat.

The role of intrathalamic GABAB neurotransmission in the control of absence seizures was investigated. In rats with genetic absence epilepsy, bilateral injections of R-baclofen (50, 100 and 200 ng/side), a selective GABAB receptor agonist, into the specific relay nuclei and the reticular nuclei of the thalamus increased spontaneous spike and wave discharges in a dose-dependent fashion, whereas injections of a GABAB antagonist CGP 35,348 (1, 2.5 and 5 micrograms/side) into the same sites decreased these seizures dose-dependently.

Wild running and switch-off behavior elicited by electrical stimulation of the inferior colliculus: effect of anticonvulsant drugs.

The behavioral and motivational effects of electrical stimulation of the inferior colliculus (IC) were investigated. Electrical stimulations of either the dorsal part or ventral part of the IC both elicited wild running (WR). Nevertheless, the ventral part was found more sensitive than the dorsal part, as lower intensities were needed to elicit WR.

Up-regulation of dopamine D2 receptor mRNA in rat striatum by chronic neuroleptic treatment.

The effect of prolonged administration of antagonists on rat striatal dopamine D2 receptor binding and mRNA content was examined. Both haloperidol (2 and 4 mg/kg) and sulpiride (10 mg/kg) induced a significant rise in total D2 and D2(444) mRNA level and in Bmax. Regulation of messenger RNA accumulation is thus an important determinant of dopamine D2 receptor density.

Evidence for a critical role of GABAergic transmission within the thalamus in the genesis and control of absence seizures in the rat.

The involvement of GABAergic transmission within the thalamus in the generation and control of spike and wave discharges (SWD) in generalized non-convulsive or absence epilepsy was studied in rats with spontaneous SWD and in non-epileptic rats. In epileptic rats, bilateral injections of gamma-vinyl GABA (GVG, 10 micrograms/side) or muscimol (10 ng/side) into the medial part of the ventral lateral thalamus, i.e.

Discriminative properties of aversive electrical stimulations of the so-called "mesencephalic locomotor region": a parametric study.

The classical 2-lever food-reward-reinforced discrimination paradigm, although already successfully applied to study discriminative properties of positively reinforcing electrical brain stimulations (EBS), has not yet been used for negatively reinforcing (aversive) EBS. This study was aimed at assessing if such a discrimination paradigm could be used to demonstrate discriminative properties of aversive EBS of the so-called "mesencephalic locomotor region" (MLR). Fourteen rats were trained for food reward to press one lever in the presence of EBS of the MLR and the other lever in the absence of EBS.

Unilateral pretectal microinjections of SR 95,531, a GABA A antagonist: effects on directional asymmetry of frog monocular OKN.

Monocular eye movements have been studied in frogs using the search coil technique before and after unilateral microinjection of SR 95,531, a GABA A antagonist, into the pretectal nuclei contralateral to the open eye. Before injection, monocular, horizontal optokinetic nystagmus (OKN) in frogs, as in other lower vertebrates, displays a directional asymmetry: the stimulation in the T-N (temporo-nasal) direction is more efficient in evoking OKN than is stimulation in the N-T (naso-temporal) direction. The N-T component is almost absent and displays only slow phases of very low speed.

Graft-induced learning impairment despite graft-enhanced cholinergic functions in the hippocampus of rats with septohippocampal lesions.

Effects of aspirative fimbria-fornix lesions and intrahippocampal grafts of fetal septal-diagonal band or hippocampal tissue were examined, in Long Evans female rats, on spontaneous alternation, radial maze learning, hippocampal acetylcholine concentrations and [3H]choline accumulation by hippocampal slices. Septohippocampal damage decreased all of these variables. Septal-diagonal band grafts increased hippocampal acetylcholine levels as well as [3H]choline accumulation of tissue (when incubated for 45 min), but they had no effect on alternation rates and further impaired radial maze performances.

Treadmill locomotion and aversive effects induced by electrical stimulation of the mesencephalic locomotor region in the rat.

The effects of electrical stimulation of the "mesencephalic locomotor region" and adjacent dorsolateral tegmentum were assessed and compared in the same rats in freely moving conditions or when lightly anesthetized and suspended over a moving treadmill. In freely moving conditions, electrical brain stimulation (EBS) of this part of the mesencephalon elicited mainly aversive effects (escape reactions: violent running and explosive jumps), but also ipsiversive circling and "gnawing." On the treadmill, EBS induced flexions of hindlimbs followed by locomotion (stepping) or flexions only.

Are soluble and membrane-bound rat brain acetylcholinesterase different?

Salt-soluble and detergent-soluble acetylcholinesterases (AChE) from adult rat brain were purified to homogeneity and studied with the aim to establish the differences existing between these two forms. It was found that the enzymatic activities of the purified salt-soluble AChE as well as the detergent-soluble AChE were dependent on the Triton X-100 concentration. Moreover, the interaction of salt-soluble AChE with liposomes suggests amphiphilic behaviour of this enzyme.

Phosphorylation by protein kinase C modulates agonist binding to striatal dopamine D2 receptors.

The effect of purified protein kinase C (PKC) on dopamine D2 receptor binding was studied. Saturation binding with [3H]spiperone was not affected. In competition experiments using agonists PKC-treated membranes showed a significant reduction in the proportion of high affinity sites, and the influence of GTP gamma S was abolished.

Differential pharmacological reactivity of aversion induced by stimulation of periaqueductal gray or mesencephalic locomotor region.

Rats were trained to switch-off aversive electrical brain stimulations applied to the periaqueductal gray (PAG) or mesencephalic locomotor region (MLR) by pressing a bar (switch-off behavior). We investigated the effects of IP injections of the benzodiazepine (BZ) receptor inverse agonist FG 7142 (2.5, 5, 10 mg/kg) or BZ receptor agonist chlordiazepoxide (CDP: 5 mg/kg) on the switch-off latency, i.

Mapping of spontaneous spike and wave discharges in Wistar rats with genetic generalized non-convulsive epilepsy.

Electrical activity was recorded in different parts of the brain in Wistar rats from a strain with genetic generalized non-convulsive epilepsy (GNCE or absence epilepsy). Movable bipolar electrodes were lowered stereotaxically by 1 mm steps into the brain in immobilized animals. Spontaneous spike and wave discharges (SWD) of the largest amplitude were recorded in the cortex and in lateral nuclei of the thalamus where they appeared occasionally to precede.

Potentiation of gamma-vinyl GABA (vigabatrin) effects by glycine.

Vigabatrin, because of its ability to increase brain GABA concentration, acts as an anticonvulsant on convulsive epileptic seizures and increases seizures in generalized non-convulsive epilepsy. Next to GABA, glycine is one of the most important inhibitory neurotransmitter amino acids. We studied the influence of glycine on the effects of treatment with vigabatrin in two rat models of generalized convulsive seizures and a rat model of spontaneous generalized non-convulsive seizures.