Chlorpromazine causes vesicle population changes in the monoaminergic synapse of the rat caudate nucleus

Summary The population of monoaminergic synaptic vesicles in the rat caudate nucleus remained unchanged or slightly decreased 3 h after chlorpromazine (CP) administration, and clearly increased after 24 h. The diameter of synaptic vesicles became smaller when the vesicles increased. These findings suggest that CP causes presynaptic blocking in part of its actions and leads to a condition in which neural transmission is inactive. In the control animals, population of the vesicles tended to fluctuate following the circadian rhythm.     

Cholinergic, monoaminergic and glutamatergic changes following perinatal asphyxia in the rat

Perinatal asphyxia (PA) is considered to lead to a variety of brain disorders including spasticity, epilepsy, mental retardation, and minimal brain disorder syndromes and may form the basis for psychiatric and neurodegenerative diseases later in life. We examined markers for neuronal transmission involved in the pathomechanisms of PA and candidates as mediators for long-term sequelae. We tested tyrosine hydroxylase (TH) and the vesicular monoamine transporter (VMAT) representing the monoaminergic system, the vesicular acetylcholine transporter (VAChT), and the excitatory amino acid carrier 1 (EAAC1), a neuronal subtype of the glutamate transporter, using immunohistochemistry on brain sections of rats subjected to graded PA. Three months following the asphyxiant insult immunoreactive (IR)-TH was decreased in striatum, hippocampus, thalamus, frontal cortex, and cerebellum; IR-VMAT was increased, and IR-VAChT was decreased in striatum. IR-EAAC1 glutamate transporter was increased in frontal cortex. The cholinergic, monoaminergic, and glutamatergic changes, still observed 3 months after the asphyxiant insult, may reflect their involvement in the pathomechanisms of PA and indicate mechanisms leading to long-term complications of PA. The variable consequences on the individual markers in several brain regions may be explained by specific susceptibility of cholinergic, monoaminergic, and glutamatergic neurons to the asphyxiant insult. Received 16 March 1999; received after revision 20 May 1999; accepted 8 July 1999     

Influence of the caudate nucleus on hippocampal afterdischarges in the rabbit

Résumé La stimulation du noyau caudé augmente et prolonge la postdécharge hippocampale chez le lapin.     

Reaching-related potentials in caudate nucleus and cerebellum of rats

Summary Electrical correlates of the lateralized reaching reaction were studied in rats with implanted electrodes. Averaged event-related potentials (ERPs) in the cerebellar dentate nucleus consisted of a negative wave coinciding with reach onset and followed 70 msec later by a positive deflection. The most prominent component of the more variable caudate ERPs was a negative wave culminating 60–120 msec after reach onset. The positive and negative ERP deflections corresponded to inhibitory and excitatory reactions respectively, at the single neuron level.     

Evaluation of monoaminergic receptors in the genetically epilepsy prone rat

Summary The intensity of sound-induced convulsions in the genetically epilepsy-prone rat (GEPR) was reduced in a dose related fashion by intracerebroventricular administration of dobutamine, (₁ agonist), terbutaline (₂ agonist) or phenylephrine (₁ agonist). BHT-920 (₂ agonist) did not cause a dose-related decrease in sound-induced convulsion intensity. Binding studies showed that whole brain and receptor densities (B_max) were normal while the K_d was increased for the ligand in GEPR brain.Acknowledgment. We are most grateful to Boehringer Ingelheim for generously supplying BHT 920. We are also indebted to Ciba-Geigy Corporation for the gift of terbutaline hydrochloride and phentolamine hydrochloride. The work was supported in part by NIH grant NS 16829.     

Evaluation of monoaminergic receptors in the genetically epilepsy prone rat

The intensity of sound-induced convulsions in the genetically epilepsy-prone rat (GEPR) was reduced in a dose related fashion by intracerebroventricular administration of dobutamine, (beta 1 agonist), terbutaline (beta 2 agonist) or phenylephrine (alpha 1 agonist). BHT-920 (alpha 2 agonist) did not cause a dose-related decrease in sound-induced convulsion intensity. Binding studies showed that whole brain alpha and beta receptor densities (Bmax) were normal while the Kd was increased for the beta ligand in GEPR brain.     

GABA in the caudate nucleus: A possible synaptic transmitter of interneurons

Summary Microiontophoretic application of GABA and its antagonist, picrotoxin, altered focal potentials evoked in the caudate nucleus by stimulation near the recording site to a much greater extent than potentials elicited by stimulation of afferent pathways, suggesting that GABA is a transmitter of interneurons in this nucleus.This study was supported by funds from the Veterans Administration and by NIH research grant No. 06820.We thank Kathleen Downes and Clifford Smathers for their assistance.     

The responsiveness of acoustic area after stimulation of the caudate nucleus

Riassunto La stimolazione ad alta frequenza e di breve durata del nucleo caudato determina inibizione dei potenziali evocati nell'area uditiva primaria e secondarie sia in animali preparati acutamente sia in animali portatori di elettrodi a dimora.     

Subcellular distribution of tyrosine hydroxylase and monoamine oxidase in the bovine caudate nucleus

Zusammenfassung Die subzelluläre Lokalisation von Tyrosin-Hydroxylase und Monoaminoxydase im Nucleus caudatus des Rindergehirns wurde untersucht. Tyrosin-Hydroxylase fand sich grösstenteils in den Synaptosomen, den Mikrosomen und dem Zytoplasma. Eine bedeutende Aktivität von Monoaminoxydase war in den Mitochondrien vorhanden.     

Pubertal changes in the medio-basal hypothalamic area after neonatal suprachiasmatic nucleus lesions in the rat

Summary In order to get more insight into the mechanism by which the onset of puberty is controlled, a developmental study on the displacement of catalase- and dopamine-containing cells in the hypothalamic region was done in rats which received a neonatal lesion of the suprachiasmatic nucleus. The displacement of cells is delayed after these lesions. However, the time lost at the beginning of the displacement is made up at the end of the migration.     

The control of amygdaloid and temporal paroxysmal activity by the caudate nucleus

Riassunto In gatti curarizzati ed in gatti portatori di elettrodi a dimora e liberi di muoversi, la stimolazione ripetitiva ad alta frequenza del nucleo caudato inibisce la comparsa sia dei fenomeni bioelettrici parossistici focalizzati nell'amigdala e nella corteccia temporale sia dei fenomeni comportamentali omologabili all'epilessia psicomotoria.

---

---

The present work is supported by a Grant from the Consiglio Nazionale delle Ricerche, Roma (Italy).     

Pubertal changes in the medio-basal hypothalamic area after neonatal suprachiasmatic nucleus lesions in the rat

In order to get more insight into the mechanism by which the onset of puberty is controlled, a developmental study on the displacement of catalase- and dopamine-containing cells in the hypothalamic region was done in rats which received a neonatal lesion of the suprachiasmatic nucleus. The displacement of cells is delayed after these lesions. However, the time lost at the beginning of the displacement is made up at the end of the migration.     

Regularly firing neurones in the rat suprachiasmatic nucleus

Summary The spontaneous discharge of some suprachiasmatic neurones in vivo and in vitro was found to exhibit a very constant interspike interval. In vivo these cells were comparatively rare and appeared to be mutually coupled. These findings are discussed in relation to coupled oscillator theories of circadian rhythm generation.