PMID: 9523594Apr 2, 1998Paper

Histamine H1 receptor antagonists produce increases in extracellular acetylcholine in rat frontal cortex and hippocampus

Journal of Neurochemistry
H C DringenbergR K Schwarting

Abstract

Lesions of the neuronal histaminergic system or pharmacological blockade of histamine receptors, e.g., with histamine H1 receptor antagonists, can enhance the performance of rats in several tests of learning and memory. The underlying neuronal systems that mediate these behavioral effects are not known. Here, we examined the effects of treatment with histamine H1 antagonists on extracellular levels of acetylcholine (ACh) in adult rats anesthetized with urethane (1.25 g/kg). ACh was quantified using in vivo microdialysis and HPLC with electrochemical detection. Basal levels of ACh in the frontal cortex and hippocampus were in the range of 0.54 +/- 0.13 and 0.96 +/- 0.17 pmol/20 min, respectively. Injection (intraperitoneally) of saline did not produce significant increases in ACh levels, even though there was a slight and gradual increase in cortical ACh levels throughout the course of the experiments (up to 4 h after an injection). Administration of the H1 receptor antagonist chlorpheniramine (intraperitoneally) produced a dose-dependent increase of cortical ACh levels to a maximum of 260, 280, and 570% of baseline values after doses of 5, 10, and 20 mg/kg, respectively. In the hippocampus, ACh content increased to a maximum of...Continue Reading

Citations

Sep 3, 2011·Journal of Neurochemistry·Christian P MüllerMaria A De Souza Silva
Mar 29, 2008·The European Journal of Neuroscience·Min-Ching Kuo, Hans C Dringenberg
Apr 18, 2008·Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology·Mei HuangHerbert Y Meltzer
Oct 7, 2000·Bulletin of Experimental Biology and Medicine·N N LermontovaS O Bachurin

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