Several direct- or indirect-acting dopamine receptor antagonists were found to decrease rat striatal acetylcholine levels. The maximum decrease of about 50% was produced by pimozide (0.5 mg/kg), by haloperidol (0.5 mg/kg) and by reserpine (2.5 mg/kg). The decreases in acetylcholine produced by pimozide and by haloperidol were found to be specific for the striatum and did not alter diencephalonic, mesencephalonic, cerebellar or hemispheric acetylcholine levels. Furthermore, these two drugs completely blocked the increase in striatal acetylcholine produced by the dopamine receptor agonist, apomorphine, and had no effect on striatal choline acetyltransferase and cholinesterase. These data suggest that haloperidol and pimozide act on the striatal cholinergic neurons through strong blockade of dopamine receptors. Reserpine presumably decreased striatal acetylcholine levels indirectly by depleting biogenic amines. Clozapine and 1-fenfluramine were unable to block the action of apomorphine, as was shown previously for chlorpromazine. It is thus suggested that these drugs are reversible dopamine receptor antagonists. Their weaker action in decreasing striatal acetylcholine may depend upon this property.

Acetylcholine↗

PubMedDate not supplied

Decrease of brain acetylcholine release in aging freely-moving rats detected by microdialysis.

In vivo extracellular acetylcholine release from brain hemispheric areas of 2-, 9-, and 18-month-old rats was measured by intracerebral microdialysis coupled with a radioenzymatic assay. Dialysis tubing was inserted transversally through both striata, frontal cortices and dorsal hippocampi 24 hours before the experiments. In the 2-month-old rats, the net average acetylcholine output, corrected for recovery and expressed in fmoles/min/single striatum, cortex and hippocampus, was 902.4 +/- 67, 303.9 +/- 14 and 334 +/- 32, respectively. In 18-month-old rats acetylcholine output was 53, 35 and 37% lower in striatum, cortex and hippocampus, respectively, than in young rats. The release from the striatum in the 9-month-old was intermediate between those of the 2- and 18-month-old rats. The intracerebroventricular injection of hemicholinium-3 caused a marked decrease in acetylcholine release from the striata of 2- and 18-month-old rats. If the decrease with hemicholinium was expressed as percent of the basal release there was no age-related difference between the young and old rats, indicating that the differences observed were due to the lower basal release found in the old rats. The possibility that the deficit in basal acetylcholine release with age may depend on a reduction of acetylcholine synthesis is discussed.

Acetylcholine↗

PubMedDate not supplied

Cross-talk between phospholipase C- and adenylate cyclase-coupled receptors in the rat hippocampus.

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Adenylyl Cyclases↗

PubMedDate not supplied

[Experience of a peripheral center in the surgical treatment of hepatic metastasis from colorectal cancer].

Surgical resection is still the first therapeutic option in patients with resectable colorectal cancer metastatic to the liver. Application of radiofrequency energy has been used in patients who did not meet the criteria for resectability and yet were candidates for a liver-directed procedure based upon the presence of liver-only disease. Hepatic resection has evolved in the last two or three decades from a procedure with associated mortality rate of up to 20% in the early 80s to usually less than 5% in patients undergoing liver resection thereafter. This improvement in morbidity and mortality is multifactorial; despite the increased safety of liver operations, hepatic resection still remains a complex surgical procedure with serious potential morbidity. The experience with liver resections and/or radiofrequency ablations, for colorectal cancer metastatic to the liver, performed at a medium-volume center (15 cases in 4 years) is presented. Some features of the metastatic disease, including the number, size and location of metastases are identified. The perioperative mortality is 0, morbidity for non surgical complications is 40%. In this series the reported overall 1-yr survival is 80%, 2-yr is 67%. This paper reviews the experienced factors that have defined the morbidity and mortality associated with liver surgery.

Colorectal Neoplasms↗