Influences of cholecystokinin antiserum on the dopamine,norepinephrine and serotonin contents of different brain regions in rats

The effects of intraventricular administration of cholecystokinin antiserum on the dopamine (DA), norepinephrine (NE) and serotonin (5-HT) contents of the hypothalamus, mesencephalon, amygdala, septum, striatum and cerebral cortex were tested 24 hr following injection in rats.Cholecystokinin antiserum decreased the DA and NE contents of the hypothalamus, mesencephalon, amygdala and septum, while it increased the DA and decreased the NE content of the striatum. In the cerebral cortex the NE content was decreased. The 5-HT contents decreased in the mesencephalon, amygdala and septum, and increased in the striatum.     

立体定向毁损大鼠杏仁核及隔核对脑内单胺类递质含量的影响

目的 :探讨杏仁核及隔核毁损后AMP模型大鼠脑内单胺类递质含量的变化。方法 :经腹腔注射苯丙胺 (amphetamine ,AMP)制作精神分裂症动物模型 ,用立体定向技术电极毁损大鼠杏仁核及隔核 ,采用荧光分光光度法和放射免疫法测定大鼠前额叶、间脑和脑干多巴胺 (DA)、5 羟色胺 ( 5 HT)和去甲肾上腺素 (NE)的含量。结果 :杏仁核及隔核毁损组前额叶DA低于模型组 (P <0 0 1) ,5 HT、NE均高于模型组 (P <0 0 1) ;杏仁核及隔核毁损组间脑DA、NE均低于模型组 (P <0 0 1) ,5 HT高于模型组 (P <0 0 1) ;脑干DA、NE均低于模型组 (P <0 0 1) ,5 HT高于模型组 (P <0 0 1)。结论 :AMP模型大鼠前额叶和脑干DA含量增高、5 HT和NE含量下降 ,间脑DA、NE含量增高、5 HT含量下降 ,立体定向毁损杏仁核及隔核能够改变脑内单胺类递质的水平。     

Effects of cholecystokinin-related peptides on self-stimulation behaviour in rats

The effects of cholecystokinin octapeptide sulfate ester (CCK-8-SE), its N-terminal tripeptide (CCK-2-4-SE) and its C-terminal tetrapeptide (CCK-5-8) were investigated on hypothalamic self-stimulation in rats. CCK-8-SE and CCK-5-8 in 400 pmole doses inhibited self-stimulation behaviour, while CCK-2-4-SE was ineffective. In 80 pmole doses the peptides showed no effect. It is suggested that CCK-5-8 itself influences self-stimulation behaviour.     

Effect of chronic nicotine administration on monoamine and monoamine metabolite concentrations in rat brain

The effects on rat brain tissue monoamine and monoamine metabolite concentrations of chronic nicotine administration at two doses (3 and 12 mg/kg/day) using constant infusion were studied. After 21 days of treatment, tissue concentrations of dopamine (DA), norepinephrine (NE), 5-hydroxytryptamine (5-HT), and several metabolites in striatum, hypothalamus, and frontal cortex were determined by high performance liquid chromatography with electrochemical detection. Compared with a control group, nicotine treatment significantly decreased NE in frontal cortex but not in other regions. The concentration of 5HT also was decreased in frontal cortex but increased in the hypothalamus at the higher dose of nicotine. The 5HT metabolite 5-hydroxyindoleacetic acid (5-HIAA) was not significantly altered in any region. The 5HT index (5-HIAA/5-HT) was significantly decreased in the hypothalamus and increased in frontal cortex at the higher dose. Concentrations of DA and the metabolite homovanillic acid (HVA) were not significantly altered by nicotine. Nevertheless, significant decreases in the DA metabolite dihydroxyphenyl-acetic acid (DOPAC) were observed in both striatum and hypothalamus. Moreover, the DA index [(DOPAC + HVA)/DA] was significantly decreased in all three brain regions. In contrast to other studies using acute dose and in vitro perfusion paradigms that have reported increased CNS catecholamine release stimulated by nicotine, chronic administration appears to be associated with decreased catecholamine turnover in some brain regions.     

Ethanol alters monoamines in specific mouse brain regions.

Ethanol (3.5 g/kg 60 min post-IP injection) produced the following changes in regional brain monoamine levels and in the respective metabolite/neurotransmitter ratios: for the noradrenergic system, MHPG was decreased in the amygdala and increased in the hypothalamus, while the MHPG/NE ratio was increased in the prefrontal cortex and the hypothalamus. For the dopaminergic system, DA was decreased in the olfactory tubercle, DOPAC was increased in the prefrontal cortex and septum, and DOPAC/DA was increased in the prefrontal cortex, septum, striatum, and hypothalamus. HVA was increased in the prefrontal cortex and septum, while HVA/DA was increased in the same regions plus the olfactory bulb. 3MT was decreased in the olfactory tubercle and striatum. The serotonergic system was not altered. The results demonstrate that ETOH produces selective regional changes in the concentration and utilization of monoamines in mouse brain with a predominant influence on dopaminergic systems and a lesser effect on noradrenergic activity.     

Effects of neurotensin on regional brain concentrations of dopamine, serotonin and their main metabolites.

The effects of neurotensin, 7.5 or 30 micrograms, on concentrations of DA, DOPAC, (HVA), serotonin 5-HT and 5-HIAA were measured in 8 regions of the rat brain either 5 or 30 min following intracerebroventricular administration. Regions examined include the frontal cortex, striatum, nucleus accumbens, amygdala, septum, hypothalamus, ventral tegmentum and substantia nigra. Results indicate that both doses of neurotensin significantly elevated concentrations of dopamine in the striatum and amygdala 5 min following injection. The effects of the peptide on DOPAC and HVA were more pervasive and enduring, with significant increases in metabolite levels occurring in both mesolimbic and nigrostriatal terminal regions. In order to assess effects on turnover of dopamine, the ratios of each metabolic to dopamine concentrations were examined. Results indicate that, while the DOPAC/DA ratio was elevated in many regions, the HVA/DA ratio was increased in all regions examined. The effects of neurotensin on serotoninergic parameters were less pervasive and more variable, with both increases and decreases in 5-HT and 5-HIAA concentrations being observed. The effects of the peptide on 5-HIAA/5-HT were limited to the nucleus accumbens, where this ratio was increased, and the ventral tegmentum, where 5-HIAA/5-HT was decreased. These findings reveal that the effects of the neurotensin on dopaminergic transmission are more widespread than previously reported in that all major dopamine pathways are affected by the peptide. Also, the observed changes in the ratios of both DOPAC and HVA to DA suggest that neurotensin enhances the turnover of this transmitter.     

Cataleptogenic and anticataleptic activity produced by cholecystokinin octapeptides in mice

The catalepsy induced by subcutaneously (sc.) and intracerebroventricularly (icv.) administered cholecystokinin octapeptide sulfate ester (CCK-8-SE) and desulfated cholecystokinin octapeptide (CCK-8-NS), and the effects of CCK-8-SE and CCK-8-NS on haloperidol-induced catalepsy, were investigated in mice. The results demonstrate the bimodal effect of CCK octapeptides in a catalepsy test. With sc. administration CCK-8-SE in the doses of 0.4 or 0.8 mumole/kg, but not CCK-8-NS at any dose, induced catalepsy. Furthermore, the catalepsy induced by CCK-8-SE was of short duration. With icv. administration only 40 pmole CCK-8-NS induced significant catalepsy. When 0.2, 0.4 and 0.8 mumole/kg sc. doses of CCK-8-NS or 0.4 pmole icv. dose of CCK-8-SE or CCK-8-NS was given in combination with intraperitoneal (ip.) administration of 1.0 mg/kg haloperidol, the total duration of catalepsy was suppressed. Finally, CCK-8-SE sc. when given in combination with haloperidol ip., exerted a biphasic, synergistic-antagonistic effect on the haloperidol-induced catalepsy.     

Effects of ketamine on dopamine metabolism during anesthesia in discrete brain regions in mice: comparison with the effects during the recovery and subanesthetic phases

The effects of ketamine on the levels of dopamine (DA), norepinephrine (NE), 5-hydroxytryptamine (5-HT, serotonin) and their metabolites were examined in discrete brain regions in mice. A high dose of ketamine (150 mg/kg, i.p.) did not change DA metabolism in the frontal cortex, nucleus accumbens, striatum and hippocampus, but did decrease it in the brainstem during anesthesia. In contrast, during recovery from the ketamine anesthesia, the high dose increased the level of homovanillic acid (HVA) in all brain regions. A low subanesthetic dose of ketamine (30 mg/kg, i.p.) increased the concentrations of both 3,4-dihydroxyphenylacetic acid (DOPAC) and HVA only in the nucleus accumbens. The DA level was not affected by any ketamine treatment. During ketamine anesthesia, the content of 3-methoxy-4-hydroxy-phenylglycol (MHPG) was decreased in the brainstem, whereas during recovery from anesthesia, the MHPG level was increased in the frontal cortex, nucleus accumbens and brainstem. The NE content was not altered in any region by ketamine treatment. The concentration of 5-hydroxyindoleacetic acid (5-HIAA) was reduced in the frontal cortex, striatum, hippocampus and brainstem during ketamine anesthesia. The 5-HT level was unaltered in all regions except the brainstem where it was reduced. In contrast, after anesthesia, the concentrations of both 5-HT and 5-HIAA were increased in the striatum. During the subanesthetic phase, however, the levels of NE, 5-HT and their metabolites were unchanged. These neurochemical results are consistent with the electrophysiological findings that a high dose of ketamine does not change the basal firing rates of nigrostriatal DA neurons during anesthesia, while low subanesthetic doses significantly increase those of ventral tegmental DA neurons.     

Late changes in cerebral monoamine metabolism following focal ventrolateral cerebrocortical lesions in rats

Twelve weeks after focal ventrolateral cerebrocortical suction lesions (ca. 12 X 4 mm) were made in rats, concentrations of the monoamines norepinephrine (NE), dopamine (DA), and serotonin (5-HT) and their metabolites were measured in several cortical and subcortical brain regions using high performance liquid chromatography with electrochemical detection. Widespread changes in the concentrations of monoamines, their metabolites, and metabolite:monoamine ratios were found in the hemisphere ipsilateral to unilateral (right) lesions, and bilaterally in animals with bilateral lesions. NE was decreased in undamaged dorsolateral cortex and hippocampus, and tended to be increased in striatum and midbrain ipsilateral to lesions. DA was increased in the hypothalamus of bilaterally lesioned animals, and also tended to be increased in striatum and midbrain. The changes of greatest magnitude and anatomical extent were found in the serotonin system: 5-HT was generally increased, and its metabolite 5-hydroxyindoleacetic acid (5-HIAA) and the 5-HIAA:5-HT ratio were decreased throughout the cerebral hemispheres ipsilateral to lesions. These widespread changes in cerebral 5-HT metabolism were qualitatively different and smaller than those previously found at 6 days after cortical lesions, and suggest a biphasic response of the ipsilateral 5-HT system to ventrolateral cortical injury.     

Effects of 8-OHDPAT administration into the dorsal raphe nucleus and dorsal hippocampus on fear behavior and regional brain monoamines distribution in rats

The effects of R(+)-8-hydroxy-dipropylaminotetralin (8-OHDPAT) administration into the dorsal raphe nucleus (DRN) or bilaterally into the dorsal hippocampus (HIP) on fear behavior in a modified version of the light-dark transitions test and regional brain monoamines (NA, DA, 5-HT) and their metabolites (MHPG, DOPAC, 5-HIAA) in the hypothalamus, midbrain central gray matter, amygdala, hippocampus and pons were examined. The experiments were performed on 36 male, 3-month old Wistar rats. Administration of 8-OHDPAT (200 ng) into the DRN reduced time out from the illuminated part of the chamber and time of motionless behavior in the illuminated part, increased the number of returns from the dark to illuminated part and number of head dipping from the dark to illuminated part without effect on time of motionless behavior in the dark part and on time of locomotor activity in the illuminated as well as in dark part of the chamber. HPLC analysis showed reduction of 5-HT content in the midbrain and amygdala, reduction of 5-HIAA content in pons, increased 5-HIAA/5-HT ratio in the hippocampus and increased DOPAC/DA ratio in the hypothalamus, midbrain, hippocampus and pons without affecting the MHPG/NA ratio and NA content. The administration of 8-OHDPAT (100 ng per site) into the HIP reduced time out from the illuminated part of chamber, time of locomotor activity in the illuminated part and head dipping from the dark to illuminated part without effect on the number of returns from the dark to illuminated part, time of locomotor activity in the dark part and time of motionless in the illuminated as well as in the dark part of chamber. HPLC analysis showed reduction of NA content in the hypothalamus, amygdala and pons, increased the MHPG content in all the investigated structures, increased MHPG/NA ratio in all the investigated structures except the hypothalamus. Dopamine content decreased in the hypothalamus and amygdala, and DOPAC/DA ratio increased in the amygdala and hippocampus. Concentrations of 5-HT, 5-HIAA and 5-HIAA/5-HT ratio were unchanged. The results obtained indicate that 8-OHDPAT acting on the pre-synaptic 5-HT1A receptors decreases fear behavior and acting on 5-HT1A post-synaptic receptors increases fear behavior in the light-dark transitions test. The neurochemical base of anxiolytic and anxiogenic effects evoked by 8-OHDPAT is being discussed.     

Sex dimorphic alterations in postnatal brain catecholarnines after gestational morphine

The concentration of brain catecholamines was measured in the hypothalamus, preoptic area (POA), frontal cortex, cerebellum, and striatum of rats exposed in utero to morphine (5–10 mg/kg/twice daily) during gestation days 11–18. Prenatal morphine induced regionally specific, sexually dimorphic alterations in male and female norepinephrine (NE), and dopamine (DA) content at different postnatal ages. Prenatal morphine significantly increased NE content in the hypothalamus of both sexes at postnatal day (PND) 23. In the POA, on the other hand, morphine increased NE content in exposed males at PND 23 and in females at PND 33. In the cerebellum, the NE content of both sexes was significantly elevated at PND 45. In the striatum, NE content was increased by the prenatal morphine only in females at PND 16. The concentration of DA was also affected in a sexually dimorphic manner. At PND 16, prenatal morphine increased the levels of hypothalamic DA only in males, and it reduced the content of DA in female but not male PDA. At PND 45, prenatal morphine increased DA in the hypothalamus of females and decreased it in males. In the cerebellum of 16-day-old morphine-exposed animals, DA levels were increased only in males; at PND 45, the levels of DA were still increased in males but had not changed in females. In the striatum, the DA content was reduced only in males at PND 16. Thus, prenatal morphine alters the development of both NE and DA neurotransmitter systems in the hypothalamus, POA, striatum, and cerebellum in a sexually dimorphic manner.     

Effects of β-/Tyr9/melanotropin-/9–18/ decapeptide on catecholamine disappearance and serotonin accumulation in discrete brain regions of rats

The effects of intracerebroventricular administration of a 1.0 ug dose of Tyr-Phe-Arg-Trp-Gly-Ser-Pro-Pro-Lys-Asp /DC-11-18/ on the α-methyl-p-tyrosine /α-MPT/-induced catecholamine disappearance and the pargyline-induced serotonin accumulation in the hypothalmus, mesencephalon, amygdala, septum, cortex and striatum were studied. The dopamine disappearance was facilitated in the septum, while it was impeded in the striatum. The norepinephrine disappearance was lowered in the amygdala. The serotonin accumulation was inhibited in the hypothalamus and enhanced in the septum. The data indicate that this decapeptide is able to modify the activities of catecholamines and serotonin in different brain regions.     

Monoamines and seizures: microdialysis findings in locus ceruleus and amygdala before and during amygdala kindling

We used microdialysis to determine extracellular concentrations of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) before and during a 1-day amygdala kindling paradigm. Subjects were young cats (<1 year old; n=8; 6 female, 2 male). Consecutive 5-min samples (2 microl/min infusion rate) were obtained from left amygdala and ipsilateral locus ceruleus complex (LC) under 3 experimental conditions lasting 1-h each (n=12 samples per cat per condition): (1) just before amygdala stimulation (baseline), (2) during focal afterdischarge (AD) and (3) during generalized AD. ADs were elicited by electrical stimulation applied to establish thresholds immediately before dialysate collection as well as during each sample collected in focal vs. generalized AD conditions. Sample concentrations were time-adjusted to correspond with sleep vs. waking state and/or focal vs. generalized ADs. Seizure activity was indexed by AD threshold (mA) and duration (s) as well as number and duration of specific clinically evident (behavioral) seizure manifestations. Main results were: (1) Lower baseline concentrations (fmoles per sample) of NE, DA and 5-HT correlated with subsequent increases in duration of focal and generalized AD as well as number of behavioral seizure correlates. (2) When compared to baseline levels, NE, DA and 5-HT concentrations significantly increased only in amygdala during focal AD and in both amygdala and LC during generalized AD. (3) NE and 5-HT concentrations were higher than DA at both collection sites and were selectively associated with increased wakefulness throughout the study.     

Selective changes in the contents of noradrenaline, dopamine and serotonin in rat brain areas during aging

This study examines the age-associated changes in noradrenaline (NA), dopamine (DA), 3,4-dihydroxyphenyl-acetic acid (DOPAC), serotonin (5-HT) and 5-hydroxy-3-indoleacetic acid (5-HIAA) in different brain areas of rats. DA and DOPAC concentrations in striatum increased at third month of age, remaining without significant variations until 12th month of age, and decreasing in 24-month-old rats. DA concentration dropped in hippocampus, amygdala and brainstem of 24-month-old-rats, whereas DOPAC levels decreased only in hippocampus. These changes suggest an age-dependent deficit of the dopaminergic system, presumably related to a reduced number/activity of DA nigrostriatal and mesolimbic neurons. An age-induced decline in NA content was found in the pons-medulla, the area containing NA neuronal bodies. Concentrations of 5-HT were reduced with aging in frontal cortex, showing a tendency to decrease in all brain areas examined. The increased 5-HIAA/5-HT ratio found in frontal cortex, amygdala and striatum suggests an age-related decreased synthesis and an accelerated 5-HT metabolism. The 5-HIAA content decreased in brainstem of the oldest rats. These findings point to a selective impairment of nigrostriatal and mesolimbic DA in aging rats, whereas reductions in NA were restricted to cell bodies region and 5-HT showed changes of different extent in areas of terminals and neuronal cell bodies.     

Comparative effects of the neurotoxins N-chloroethyl-N-ethyl-2-bromobenzylamine hydrochloride (DSP4) and 6-hydroxydopamine on hypothalamic noradrenergic, dopaminergic and 5-hydroxytryptaminergic neurons in the male rat

The intracerebroventricular (i.c.v.) administration of 6-hydroxydopamine (6-OHDA; 50 micrograms X 3) and the systemic administration of DSP4 (50 mg/kg X 2; i.p.), alone and in combination, were compared for their abilities to alter the concentrations of norepinephrine (NE), dopamine (DA), dihydroxyphenylacetic acid (DOPAC) and 5-hydroxytryptamine (5-HT) in selected hypothalamic and extra-hypothalamic (striatum, frontal cortex, hippocampus) regions of the male rat brain. DSP4 markedly lowered NE concentrations in extrahypothalamic regions, and within the hypothalamus produced a mild and variable reduction of NE without altering concentrations of DA, DOPAC or 5-HT. 6-OHDA markedly lowered NE concentrations in all brain regions, but was without effect on DA, DOPAC and 5-HT concentrations in any region analyzed. Combined treatment with DSP4 and 6-OHDA did not produce additional effects on levels of NE, DA and DOPAC over either drug alone, but did cause a mild reduction of 5-HT in several brain regions. These results indicate that systemic treatments with DSP4 per se are not as effective as i.c.v. 6-OHDA in depleting NE in the hypothalamus, and that when the two neurotoxins are administered there appears to be some destruction of 5-HT neurons.     

Effects of neonatal rat Borna disease virus (BDV) infection on the postnatal development of the brain monoaminergic systems

Effects of neonatal Borna disease virus infection (BDV) on the postnatal development of brain monoaminergic systems in rats were studied. Tissue content of norepinephrine (NE), dopamine (DA) and its metabolite, 3,4-dihydroxyphenol acetic acid (DOPAC), and serotonin (5-HT) and its metabolite, 5-hydroxyindole-3-acetic acid (5-HIAA) were assayed by means of HPLC-EC in frontal cortex, cerebellum, hippocampus, hypothalamus and striatum of neonatally BDV-infected and sham-inoculated male Lewis rats of 8, 14, 21, 60 and 90 days of age. Both NE and 5-HT concentrations were significantly affected by neonatal BDV infection. The cortical and cerebellar levels of NE and 5-HT were significantly greater in BDV-infected rats than control animals at postnatal days (PND) 60 and 90. Tissue content of NE in hippocampus was unaffected. In hippocampus, neonatally BDV-infected rats had lower 5-HT levels at PND 8 and significantly elevated levels at PND 21 and onwards. Neither striatal levels of 5-HT nor hypothalamic levels of 5-HT and NE were affected by neonatal BDV infection, suggesting that the monoamine systems in the prenatally maturing brain regions are less sensitive to effects of neonatal viral infection. 5-HIAA/5-HT ratio was not altered in BDV-infected rats indicating no changes in the 5-HT turnover in the brain regions damaged by the virus. Neither DA nor DOPAC/DA ratio was affected by neonatal BDV infection in any of the brain regions examined. The present data demonstrate significant and specific alterations in monoaminergic systems in neonatally BDV-infected rats. This pattern of changes is consistent with the previously reported behavioral abnormalities resulting from neonatal BDV infection.     

Variability among brain regions in the specificity of 6-hydroxydopamine (6-OHDA)-induced lesions

Summary 6-Hydroxydopamine (6-OHDA; 200 g, 150 g or 110 g) or vehicle was infused stereotaxically into the lateral ventricles of rats, usually following pretreatment with desmethylimipramine (DMI). Various brain regions were then assayed for dopamine (DA), serotonin (5-HT) and norepinephrine (NE). As expected, 6-OHDA depleted DA in all brain regions examined. Unexpectedly, however, the two highest doses of 6-OHDA significantly decreased 5-HT levels in the hippocampus and increased 5-HT levels in the striatum. In addition, despite pretreatment with doses of DMI commonly considered adequate to block 6-OHDA-induced depletion of NE, all doses of 6-OHDA tested significantly reduced NE levels in the hippocampus, hypothalamus and septum.We interpret our data as suggesting that some brain regions are susceptible to nonspecific toxic effects of 6-OHDA at doses commonly employed. Furthermore, these nonspecific effects may or may not occur, depending on seemingly minor variations in experimental technique.     

杏仁核亚核群毁损对PCP模型大鼠行为和递质的影响

目的探讨杏仁核亚核群毁损后五氯苯酚(pentachlorophenol,PCP)模型大鼠行为和前额叶单胺类递质含量的变化,为立体定向技术治疗精神病提供参考。方法经腹腔注射PCP制作精神分裂症动物模型,立体定向电极毁损大鼠杏仁核,对其刻板行为进行评分,应用高效液相色谱分析系统检测前额叶多巴胺(DA)、5-羟色胺(5-HT)和去甲肾上腺素(NE)的含量。结果杏仁核内侧核群毁损能减轻PCP模型大鼠的刻板行为和社会行为,与假毁损组之间具有非常显著性差别(P<0.001)。毁损组前额叶DA含量低于假毁损组(P <0.05),5-HT和NE含量均高于假毁损组(P<0.05)。结论PCP模型大鼠前额叶DA含量增高,5-HT和NE含量下降。立体定向毁损杏仁核内侧核群能够改变前额叶单胺类递质的水平,改善模型大鼠精神分裂症症状。     

Analysis of temporal and dose-dependent effects of estrogen on monoamines in brain nuclei

Levels of norepinephrine (NE), dopamine (DA) and serotonin (5-HT) were measured in hypothalamic and limbic nuclei of ovariectomized rats after various doses of estradiol and at various intervals after estradiol administration. Of 13 areas examined, time- and dose-dependent effects of estrogen on monoamine content were restricted to only a few, discrete areas which concentrate estradiol. Subcutaneous administration of 1-50 micrograms of estradiol benzoate (EB) and measurement of monoamines 24 h later was associated with dose-dependent increases of NE in the medial preoptic nucleus, diagonal band nucleus and periventricular area of the anterior hypothalamus, and increased levels of DA in the periventricular area of the preoptic area. No changes were found in 5-HT levels, but dose-dependent increases in the level of the 5-HT metabolite, 5-hydroxyindole acetic acid (5-HIAA), were measured in the lateral portion of the ventromedial nucleus. Effects of 5 micrograms of EB were evaluated at 1.5, 6, 12 and 45 h after administration. No changes were noted at 1.5 h, but 5-HIAA in the ventromedial nucleus was elevated at 6 and 12 h. NE levels were elevated at 12 and 45 h in the diagonal band and preoptic nuclei and at 45 h in the lateral septum and periventricular area of the hypothalamus. DA levels decreased in the arcuate-median eminence area 45 h after estrogen. Intravenous administration of 10 micrograms of estrogen and measurement of monoamines 1 h later was not associated with altered levels of any monoamine suggesting that the estrogen-dependent changes are consistent with the genomic model for steroid hormone action.(ABSTRACT TRUNCATED AT 250 WORDS)