Sexually Dimorphic Anxiety-Like Interoceptive Discriminative Stimuli
Abstract
Jung, Marianna E., Sexually Dimorphic Anxiety-Like Interoceptive Discriminative Stimuli. Doctor of Philosophy (Biomedical Sciences), December 1997, 150 pp, introduction, 2 chapters, discussion, bibliography, 109 titles. This study compared gender differences in the anxiogenic stimuli induced by either a GABA-A antagonist, pentylenetetrazol (PTZ) or by a 5-HT1b/2 agonist, m-chlorophenylpiperazine (m-CPP) before and during ethanol withdrawal (EW). Rats were trained to discriminate either PTZ (16mg/kg, IP) or m-CPP (1.2 mg/kg, IP) from saline in a two lever choice task for food reward. Male and female rats were gonadectomized or sham-operated, and ovariectomized (OVX) female rats were tested during replacement treatment with 17β estradiol (2.5 mg, 21 day release, sc). The dose-response for the discrimination of the interoceptive stimulus (IDS) produced by PTZ (0-16 mg/kg) or m-CPP (0 to 1.2 mg/kg) was measured under all hormonal conditions. For m-CPP trained rats, latency to first lever-press response was also tested. Results: sham and estradiol-replaced female rats had higher ED50s for discrimination of the PTZ or m-CPP IDS than intact males or OVX rats. There is a dose-related impairment of operant responding after mCPP injection. Sham and estradiol replaced OVX rats showed an increased delay to the initiation of response after m-CPP injection as compared to sham or castrated male rats or OVX rats that showed no effect at the doses tested. Rats then received a chronic ethanol diet (6.5%) for 10 days. At twelve hours of ethanol withdrawl, they were tested for lever selection after saline injection. Fewer sham female and estradiol-replaced female rats responded on the drug lever during acute EW as compared to sham male, castrated or OVX rats. In general, the anxiogenic drug lever selection of OVX rats resembled that of male rats but was restored toward that of sham female rats by estradiol replacement. Castration did not alter the response of male rats to either PTZ or mCPP. Serum β –estradiol concentrations were determined by radioimmunoassay for sham, OVX, and estradiol-replaced female rats. The concentration was significantly higher in hormone-replaced female rats than in OVX. The estradiol concentration in sham female rats showed a cyclic pattern over 4 consecutive days, but this pattern did not correlate with any difference in IDS. Blood ethanol concentration (BEC) was determined using head space gas chromatography. BEC was higher in intact female rats than in intact male rats after ethanol injection (2 g/kg, ip), but did not differ during EW. Conclusions: females produce less anxiogenic IDS in response to either GABA inhibition or 5-HT1b/2 activation, but are more impaired by m-CPP in their ability to initiate operant responses than male rats. In addition, fewer intact females developed a spontaneous IDS during EW than males which is not the result of lower BEC. Estrogen appears to play a trophic role in altering responsiveness to anxiogenic stimuli.
Subject
Animal Sciences
Animal Structures
Behavioral Neurobiology
Behavior and Behavior Mechanisms
Biochemical and Biomolecular Engineering
Biochemistry
Biology
Biomedical
Catalysis and Reaction Engineering
Cell and Developmental Biology
Cell Biology
Chemical Actions and Uses
Chemicals and Drugs
Cognitive Neuroscience
Comparative and Laboratory Animal Medicine
Ecology and Evolutionary Biology
Life Sciences
Medical Cell Biology
Medicine and Health Sciences
Molecular and Cellular Neuroscience
Molecular Biology
Nervous System
Nervous System Diseases
Neuroscience and Neurobiology
Neurosciences
Other Neuroscience and Neurobiology
Other Nutrition
Pharmacy and Pharmaceutical Sciences
Physiological Processes
Reproductive and Urinary Physiology
Signal Processing
Structural Biology
Substance Abuse and Addiction
Systems and Communications
Systems Neuroscience
Therapeutics
Veterinary Toxicology and Pharmacology
Sexually dimorphic anxiety-like discriminative stimuli
anxiogenic stimuli
GABA-A antagonist
pentylenetetrazol
m-chlorophenylpiperazine
gonadectomize
ovariectomize
interoceptive stimulus
ethanol diet
ethanol withdrawl
lever selection
saline injection
estradiol concentration
blood ethanol concentration
GABA inhibition
5-HT1b/2 activation
Animal Structures
Behavioral Neurobiology
Behavior and Behavior Mechanisms
Biochemical and Biomolecular Engineering
Biochemistry
Biology
Biomedical
Catalysis and Reaction Engineering
Cell and Developmental Biology
Cell Biology
Chemical Actions and Uses
Chemicals and Drugs
Cognitive Neuroscience
Comparative and Laboratory Animal Medicine
Ecology and Evolutionary Biology
Life Sciences
Medical Cell Biology
Medicine and Health Sciences
Molecular and Cellular Neuroscience
Molecular Biology
Nervous System
Nervous System Diseases
Neuroscience and Neurobiology
Neurosciences
Other Neuroscience and Neurobiology
Other Nutrition
Pharmacy and Pharmaceutical Sciences
Physiological Processes
Reproductive and Urinary Physiology
Signal Processing
Structural Biology
Substance Abuse and Addiction
Systems and Communications
Systems Neuroscience
Therapeutics
Veterinary Toxicology and Pharmacology
Sexually dimorphic anxiety-like discriminative stimuli
anxiogenic stimuli
GABA-A antagonist
pentylenetetrazol
m-chlorophenylpiperazine
gonadectomize
ovariectomize
interoceptive stimulus
ethanol diet
ethanol withdrawl
lever selection
saline injection
estradiol concentration
blood ethanol concentration
GABA inhibition
5-HT1b/2 activation
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