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Effects of Allopregnanolone on the EEG of Alcohol‐Preferring and Alcohol‐Nonpreferring Rats
Author(s) -
Slawecki C. J.,
Purdy R. H.,
Li TK.,
Walpole T.,
Ehlers C. L.
Publication year - 2000
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.2000.tb02105.x
Subject(s) - allopregnanolone , alcohol , electroencephalography , neuroactive steroid , endocrinology , chemistry , medicine , psychology , neuroscience , biochemistry , gabaa receptor , receptor
Background: Alcohol preferring (P) and alcohol‐nonpreferring (NP) rats have been shown to have differing behavioral and electrophysiological responses to drugs that are positive modulators of the γ‐aminobutyric acid type A (GABA‐A) receptor complex, such as ethanol and benzodiazepines. The neuroactive steroid allopregnanolone is also a positive modulator of GABA‐A receptors; therefore, we hypothesized that P and NP rats would respond differently to intraperitoneally administered allopregnanolone. Methods: Male P and NP rats were implanted with screw electrodes that overlay the frontal and parietal cortices and with a depth electrode aimed at the amygdala. Allopregnanolone (0.0–10.0 mg/kg ip) was administered 10 min before recording the EEG. Results: Allopregnanolone increased high‐frequency power (8–32 Hz) in the cortex and amygdala of both P rats and NP rats. In addition, allopregnanolone increased the predominant frequency of the cortical EEG in the 8 to 16 Hz bandwidth, decreased the predominant frequency in the 32 to 50 Hz bandwidth, and increased EEG variability (16–50 Hz). The effects of allopregnanolone were qualitatively similar in P and NP rats. However, P rats were more sensitive to low doses of allopregnanolone in cortex, whereas NP rats responded to lower doses of allopregnanolone in the amygdala. Conclusions: These data indicate that P and NP rats differ in their sensitivity to the EEG effects of allopregnanolone in the cortex and amygdala, which suggests that differences in GABAergic systems between P and NP rats may contribute to some of the differences observed in their behavioral repertoire.