Effect of different feeding schedules on food intake in caudate lesioned rats.

Inbred albino rats were exposed to different feeding schedules before and after caudate nucleus lesions. The animals show adaptation to the new patterns of food deprivation even after caudate nucleus lesions. However, the lesioned animals are not able to elevate their food intake or body weight to the prelesion levels. These findings suggest that feeding, satiety and body weight mechanisms are disturbed in the absence of intact caudate nucleus, possibly due to removal of nigro-striatal dopamine influence.

Role of caudate nucleus on modulation of blood pressure responses in cat.

Changes in blood pressure, heart rate and respiration were studied in 15 cats on bilateral stimulation of rostral, middle and caudal regions of caudate nucleus. Hypotensive response was obtained on stimulation of anterior caudate nucleus, which changed to pressor response when posterior caudate nucleus was stimulated. Biphasic blood pressure responses were recorded on stimulation of middle caudatal area. No detectable changes were observed on heart rate and respiration. This suggests a role for caudate nucleus as a modulator in blood pressure regulation.

Effects of chronic treatment with high doses of chlorpromazine on ATP and ADP hydrolysis by synaptosomal fractions from the rat caudate nucleus

Several studies have indicated that chlorpromazine and its metabolites affect ATP hydrolysis by brain and liver plasma membranes in vitro. The present report examines whether chronic treatment (12 days) with high doses of chlorpromazine (10 and 40 mg/kg) could affect ATP and ADP hydrolysis by synaptosomal fractions from the rate caudate nucleus. Both doses of chlorpromazine caused significant and paralled decreases (23 to 31%) in the ATP and ADP hydrolysis. The parallelism between the effects of chlorpromazine on ATP and ADP hydrolys suggests the participation of a single enzyme (ATP diphosphohydrolase) in nucleotide hydrolysis

Pentylenetetrazol (PTZ)-kindling development in intact and subcortical structure lesioned rats.

Kindling was induced in male wistar rats (280-320 g) by daily ip injections of PTZ in subthreshold doses (30 mg/kg). Repeated administration of PTZ to animals resulted in developing of enhanced seizures and also enhanced seizure susceptibility which could be sustained for a long time (6 months) after last seizure paroxysm. The lesioned hippocampus retarded the manifestation of PTZ kindling, where as lesioned caudate nuclei increased the seizure kindling development. Results also revealed hippocampus as a determinant structure in PTZ kindling formation, which stabilize the epileptic manifestations and make them chronic, at the same time caudate nuclei retarded the epileptic seizures stabilization. This role may be only antiepileptic, and not anti-kindling as is known for caudate nuclei.

Role of mid-dorsal caudate nucleus in maintenance of body weight in rats on administration of foods with different caloric densities.

Rats were fed with food of different caloric densities by addition of kaolin or groundnut oil to the normal food powder. The food intake, caloric intake and body weights were noted. These observations were compared before and after bilateral destruction of mid-dorsal caudate nucleus. The food intake before caudatal lesion varied appropriately with the caloric density of food thus maintaining caloric intake and body weight. After mid-dorsal caudatal destruction this feedback mechanism of maintaining body weight was operative with low caloric density diet but not with high caloric diet.

Sensorimotor changes following lesion of mid-dorsal caudate nucleus in rats.

Effects of mid-dorsal caudate nucleus on sensorimotor changes were studied in rats. After electrolytic lesion of this area of brain there was impairment in sensory functions and decline in motor component was observed to be statistically significant.

Papel del complejo pulvinar-lateral posterior en la respuesta de rotación: relación con otras estructuras cerebrales; sistemas farmacológicos implicados en esta conducta / Role of pulvinar lateralis posterior complex on rotation response: relation with other cerebral structures; pharmacological systems involved in this behavior

Se hace un análisis crítico de los resultados obtenidos en 4 series experimentales efectuadas en gatos. En estos experimentos se muestran los resultados siguientes: 1) la estimulación eléctrica del completo pulvinar-lateral posterior (P-LP) evoca ratación contralateral de la cabeza, acompañada de una rotación de ambos ojos en la misma dirección, la mayor parte de las veces de tipo sacádico. Con intensidades de corriente superior se produce rotación contralaterl de todo el cuerpo; 2) las eferencias desde el P-LP para producir estos efectos se hacen a través del colículo superior ipsilateral. La lesión electrolítica de esta última estructura suprime la conducta de rotación inducida por estimulación elétrica del P-LP. Este resultado no se obtiene cuando es lesionado el núcleo causado o el centralis later alis; 3) la ablación de la corteza cerebral ipsilateral, que tiene conexiones recíprocas importantes con el P-LP. produce la supresión de la respuesta de rotación en el 50 % de los gatos en la primeira semana que sigue a la resección cortical. Sin embargo, 30 días después de la ablación, el 86 % de los electrodos implantados en en P-LP son capaces de inducir, por estimulación elétrica, la respuesta de rotación, y 4) la inyección local en el P-LP a través de una cánula de carbacol o dioxolano, este último activador exclusivo de los receptores muscarínicos, produce también respuesta de rotación contralateral de cabeza-ojo-cuerpo. Los resultados expuestos nos permiten postular que el P-LP es otra estructura cerebral relacionada con rotación y diferente del sistema nigro-estriatal. Este último no es afectado por lesión del colículo superior, como sucede con el P-LP. Por otra parte, el neurotransmisor más importante implicado en la conducta de rotación en el sistema nigro-estriatal es la dopamina, en tanto que en el P-LP es la acetilcolina

Effect of bilateral caudatal lesion on pain threshold in rats.

Pain threshold was determined in eleven adult male rats (Haffkine strain) on electrical stimulation of midpart of tail. Three responses, namely tail withdrawal, vocalization and vocalization afterdischarge were studied. Of these eleven animals, seven in experimental group were subjected to bilateral electrolytic lesion of mid-dorsal caudate nucleus while remaining four animals were sham operated. The increase in pain threshold after caudatal destruction for all the three responses suggests the possible modulatory role of mid-dorsal caudate nucleus in the mechanism of pain.