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Anesthetics decreased the microdialysis extraction fraction of norepinephrine but not dopamine in the medial prefkontal cortex
Author(s) -
Pan Wynn H. T.,
Lai YuJun
Publication year - 1995
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890210112
Subject(s) - chloral hydrate , microdialysis , pentobarbital , chemistry , extracellular , in vivo , chloral , sodium , extracellular fluid , anesthesia , endocrinology , medicine , pharmacology , biochemistry , biology , microbiology and biotechnology , organic chemistry
We evaluated the effects of chloral hydrate and pentobarbital sodium on the basal extracellular concentrations of dopamine (DA) and norepinephrine (NA) as well as their in vivo extraction fraction (relative recovery) at the medial prefrontal cortex (mPFC) in rats by using zero‐net flux microdialysis method. Adult, male Sprague‐Dawley rats anesthetized with either chloral hydrate (400 mg/kg, i.p., with 80 mg/kg i.v. supplements) or pentobarbital sodium (50 mg/kg, i.p., with 10 mg/kg i.v. supplements) were used as treatment groups. Conscious rats were used as a control group. The basal extracellular concentration and in vivo recovery of DA in the conscious group were 2.38 ± 0.70 nM and 41 ± 6%. In comparison with the chloral hydrate group (1.51 ± 0.55 nM and 41 ± 9%) and the pentobarbital sodium group (2.81 ± 1.20 nM and 42 ± 4%), there were no significant effects of anesthesia on the basal extracellular concentration and the in vivo recovery of DA at the mPFC. Additionally, the basal extracellular concentration and the in vivo recovery of NA in the conscious group were 1.59 ± 0.37 nM and 51 ± 8%. There also were no significant differences of the basal extracellular concentration of NA among these three groups (chloral hydrate group: 4.38 ± 1.39 nM; pentobarbital group: 3.67 ± 0.90 nM). However, the conscious group had a higher in vivo recovery than the two anesthetized groups (chloral hydrate group: 16 ± 2%; pentobarbital group: 27 ± 5%). Based on these findings, we then concluded that pentobarbital sodium and chloral hydrate selectively suppressed NA's active processes (such as release, reuptake, and metabolism) but not DA's yet do not affect the basal extracellular concentrations of NA and DA at the mPFC. Therefore, anesthesia was accompanied by a selective change of the active processes of certain types of neurons but not by altering their basal extracellular concentrations. However, more studies are necessary to draw a relationship between these findings and the action of general anesthesia. © 1995 Wiley‐Liss, Inc.