Estrogen effects on tyrosine hydroxylase-immunoreactive cells in the ventral mesencephalon of the female rat: further evidence for the two cell hypothesis of dopamine function

Zsarnovszky, Attila; Scalise, Trudy J; Horváth, Tamas L.; Naftolin, Frederick

doi:10.1016/s0006-8993(00)02323-4

Cited by 10 publications

(10 citation statements)

References 10 publications

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“…These results are not entirely consistent with previous findings, suggesting potential species differences in hormonal regulation of TH expression, some of which may reflect variation between opportunistic and seasonal breeders. The lack of E2 effects on the VTA cell group, which differs from previously reported findings in mammals and birds [45,88], is particularly notable in this regard. However, it is important to keep in mind that subtle effects of estradiol manipulation on dopaminergic neurons may not have been detected because we did not examine TH mRNA within this study.…”

Section: Discussioncontrasting

confidence: 98%

Estrogenic regulation of dopaminergic neurons in the opportunistically breeding zebra finch

Kabelik

Schrock

Ayres

et al. 2011

General and Comparative Endocrinology

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Steroid-induced changes in dopaminergic activity underlie many correlations between gonadal hormones and social behaviors. However, the effects of steroid hormones on the various behaviorally relevant dopamine cell groups remain unclear, and ecologically relevant species differences remain virtually unexplored. We examined the effects of estradiol (E2) manipulations on dopamine (DA) neurons of male and female zebra finches (Taeniopygia guttata), focusing on numbers of tyrosine hydroxylase-immunoreactive (TH-ir) cells in the A8–A15 cell groups, and on TH colocalization with Fos, conducted in the early A.M., in order to quantify basal transcriptional activity. TH is the rate-limiting enzyme for catecholamine synthesis, and specifically DA in the A8–A15 cell groups. In contrast to other examined birds and mammals, reducing E2 levels with the aromatase-inhibitor Letrozole failed to alter TH-ir neuron numbers within the ventral tegmental area (VTA; A10), while increasing neuron numbers in the central gray (CG; A11) and caudal midbrain A8 populations. Consistent with findings in other birds, but not mammals, we also found no effects of E2 manipulations (Letrozole or Letrozole plus E2 replacement) on TH-Fos colocalization in any location. In accordance with previous observations in both mammals and birds, E2 treatment decreased the number of TH-ir neurons in the A12 population of the tuberal hypothalamus, a cell group that inhibits the release of prolactin. In general, males and females exhibited similar TH-ir neuron numbers, although males exhibited significantly more TH-ir neurons in the A11 CG population than did females. These results suggest partial variability in E2 regulation of DA across species.

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Section: Discussioncontrasting

confidence: 98%

Estrogenic regulation of dopaminergic neurons in the opportunistically breeding zebra finch

Kabelik

Schrock

Ayres

et al. 2011

General and Comparative Endocrinology

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“…We note, however, that our results do not rule out additional effects of aromatization and estrogens on TH cell populations. In rats, estrogens have significant negative effects on some hypothalamic TH populations [36, 37], and some mesencephalic dopaminergic neurons [8]. Future studies are needed to assess estrogenic effects in amphibians.…”

Section: Discussionmentioning

confidence: 99%

“…Gonadal steroids play a major role in influencing the activity of the dopaminergic systems that underlie the neural control of reproductive behaviors [1, 4, 6, 7, 8]. In addition to regulating dopaminergic control of behavior, gonadal steroids also influence several dopaminergic cell populations that regulate neuroendocrine control of reproduction.…”

Section: Introductionmentioning

confidence: 99%

Androgen Effects on Tyrosine Hydroxylase Cells in the Northern Leopard Frog, <i>Rana pipiens</i>

Chu

Wilczynski

2002

Neuroendocrinology

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The interaction between gonadal steroids and dopamine neurons has been examined extensively in rodent model systems. However, there have been few investigations examining the functional relation between gonadal steroids and dopaminergic systems in nonmammalian taxa, and none in amphibians. We examined the effects of testosterone (T) and dihydrotestosterone (DHT) on changes in tyrosine hydroxylase immunoreactive (TH-ir) neuron number in the fore- and midbrain of male Rana pipiens, the Northern leopard frog, using a whole-mount immunohistochemical procedure. Gonadectomized males had significantly fewer TH-ir neurons in the medial preoptic area (POA), suprachiasmatic nucleus (SCN), and the caudal hypothalamus/posterior tubercular region (HY/TP) compared with T-implanted males. A follow-up study demonstrated that T- and DHT-implanted males had similar numbers of TH-ir neurons in these three regions compared with intact males and that all three of these groups possessed significantly more TH-ir neurons compared with gonadectomized males. These results suggest that circulating sex steroids have a significant impact on the activity of dopaminergic neurons in male R. pipiens. Although the function of these specific dopaminergic neurons is not yet known, the POA, SCN, and TP/DH are known to be integral brain regions underlying the neural control of reproductive behavior in frogs. These results suggest that dopamine may be important in controlling the behavior or neuroendocrine mechanisms of reproduction in these animals and that dopaminergic activity in these areas is regulated by gonadal steroids.

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“…Estradiol was found to increase tyrosine hydroxylase immunoreactive neurons in the substantia nigra of rats, while in macaques, this effect was observed in the caudate nucleus and putamen [83,84] .…”

Section: Estradiol and Dopaminementioning

confidence: 93%

Effect of Gonadal Hormones on Neurotransmitters Implicated in the Pathophysiology of Obsessive-Compulsive Disorder: A Critical Review

Karpinski

Mattina

Steiner³

2016

Neuroendocrinology

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Obsessive-compulsive disorder (OCD) is a relatively common neuropsychiatric disorder affecting between 1.6 and 3.2% of the population. A number of studies have previously reported increased incidence of OCD, or exacerbation of preexisting symptoms in females during reproductive events. Since these periods are known to involve fluctuating levels of gonadal hormones, these steroids have been suggested to be involved in modulating the course of the disorder. However, to date, only a few studies have measured hormone levels and obsessive-compulsive (OC) symptoms concurrently; thus, direct evidence for this relationship is limited. In turn, investigations into neurotransmission in OC individuals have been more extensive, and have implicated the serotonergic, dopaminergic, and glutamatergic neurotransmitter systems in OCD pathology. There is evidence suggesting that reproductive hormones estrogens and progesterone can modulate neurotransmission in the aforementioned signaling pathways by regulating the expression of receptors and channels, as well as the synthesis and release of the neurotransmitter itself. Overall, estrogen and progesterone appear to enhance serotonin signaling, which has been associated with improved OC symptoms. The effect of the gonadal hormones in dopaminergic and glutamatergic signaling is much more variable, highlighting the need for further research in this field. The existing evidence shows that gonadal hormones can have profound impacts on neurotransmission in the brain, leading to the conclusion that the hormonal fluctuations during reproductive events are a plausible factor contributing to the change in OCD course during these times.

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Estrogen effects on tyrosine hydroxylase-immunoreactive cells in the ventral mesencephalon of the female rat: further evidence for the two cell hypothesis of dopamine function

Cited by 10 publications

References 10 publications

Estrogenic regulation of dopaminergic neurons in the opportunistically breeding zebra finch

Estrogenic regulation of dopaminergic neurons in the opportunistically breeding zebra finch

Androgen Effects on Tyrosine Hydroxylase Cells in the Northern Leopard Frog, <i>Rana pipiens</i>

Effect of Gonadal Hormones on Neurotransmitters Implicated in the Pathophysiology of Obsessive-Compulsive Disorder: A Critical Review

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