Potential utility of rubidium 82 PET quantification in patients with 3-vessel coronary artery disease.

Background: Standard perfusion imaging may underestimate the extent of disease in 3-vessel coronary atherosclerosis. This study determined whether positron emission tomography quantification of perfusion reserve by use of rubidium 82 net retention defined a greater extent of disease than the standard approach in patients with 3-vessel disease.

Methods And Results: Rb-82 net retention was quantified as an estimation of absolute perfusion at rest and with dipyridamole stress by use of dynamic positron emission tomography imaging.

Chlordiazepoxide, go-nogo successive discrimination and brain biogenic amines in cats.

Chlordiazepoxide (CDP; 0.4 mg/kg/day, per os) was administered to cats during either the acquisition (CDP 21-22 days) of a go-nogo successive discrimination task (SD) or the performance (CDP 10 days) of the previously learned SD task. Endogenous levels of serotonin, 5-hydroxyindoleacetic acid, noradrenaline and dopamine were assayed in 12 brain areas, in trained as well as in untrained cats.

Zona incerta and lateral hypothalamic afferents to the midbrain reticular core of cat--HRP and electrophysiological study.

The zona incerta (ZI) and lateral hypothalamic afferents to the midbrain reticular formation (MRF) of cat were investigated with the horseradish peroxidase (HRP) technique and by using antidromic identification in experiments on chronically implanted, behaving preparations. Following HRP injections restricted to the MRF territory (nucleus cuneiformis and central tegmental field), the largest number of retrogradely labeled cells appeared in the medial third of the ipsilateral ZI. Labeling extended medially to the adjacent lateral hypothalamus.

Effects of chlordiazepoxide on acquisition and performance of a go-no go successive discrimination task, and on brain biogenic amines in cats.

1. Normal and chlordiazepoxide (0.4 mg/kg/day, per os) treated cats were trained on a symmetric go-no go successive discrimination task with positive reinforcement.

Immediate behavioral effects of kainic acid injections into the midbrain reticular core.

Microinjections of kainic acid into the midbrain reticular core were performed in chronically implanted, unanesthetized cats. The immediate effects of kainate excitation were studied during the first 8 h, in animals without any behavioral or EEG signs of epilepsy. Animals displayed pupillary dilatation, piloerection, accelerated respiration, a frozen attitude with a complete lack of facial expression, and no or only very slight orienting reactions.

Excitatory-inhibitory processes in parietal association neurons during reticular activation and sleep-waking cycle.

Excitatory-inhibitory processes of parietal association neurons were studied during reticular-induced EEG activation and natural sleep-waking cycle. The probability of antidromic invasion in long-axon cells is enhanced following midbrain reticular stimulation and during both waking (W) and desynchronized sleep (D) states compared to slow-wave sleep. The thalamically elicited inhibitory phase occurs with a shorter latency following reticular stimulation and during W and D states; this is due to the reduced duration, during all these experimental conditions, of secondary excitatory processes.

A study of geniculate unit activity during cryogenic blockade of the primary visual cortex in the cat.

In cats under nembutal or chloralose anesthesia, unilateral temporary cryogenic blockades of the primary visual cortex were performed and their influence on unitary responses to restricted light spots was tested in the ipsilateral geniculate nucleus. No significant effect could thus be observed, at variance with previous positive results obtained by our group in structures like superior colliculus and pulvinar complex using the same experimental procedure.