Evidence for an Inhibitory Dopaminergic and Stimulatory Noradrenergic Hypothalamic Influence on PMS-Induced Ovulation in the Immature Rat. II. A Pharmacological Analysis

Löfström, Anders; Lf, Agnati; Fuxé, Kjell; Hökfelt, T

doi:10.1159/000122717

Cited by 16 publications

(8 citation statements)

References 14 publications

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“…Recently, it has been suggested that multiple hypothalamic DA systems may be controlling LH release with the TIDA or A12 neurons being inhibitory (and, perhaps stimulatory at higher doses) while the incertohypothalamic or AI3 DA system may be stimulatory to gonadotrophin release [3,[12][13][14][15][16][17], An involvement of the incertohypothalamic A 13 system in LH release was first demonstrated by Wikes et al [16] who showed that lesions of the zona incerta resulted in decreased levels of LHRH in the median eminence. This suggests that A13 DA neurons may be involved in the regulation of LHRH syn thesis or its release from LHRH terminals in the median emi nence.…”

Section: Discussionmentioning

confidence: 99%

Effect of Medial Zona Incerta Lesions on the Ovulatory Surge of Gonadotrophins and Prolactin in the Rat

Sanghera¹,

Anselmo-Franci²,

McCann³

1991

Neuroendocrinology

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Bilateral electrolytic lesions of the incertohypothalamic A13 dopamine (DA) system were made on the morning of proestrus in female rats with regular estrous cycles under ether anesthesia. Hourly blood samples were withdrawn, via a jugular catheter from conscious, freely moving rats, between 14.00 h and 18.00 h on the afternoon of proestrus. Plasma LH, FSH and prolactin levels were determined by RIA. The preovulatory surges of LH and prolactin were blocked in animals in which the A13 DA nucleus was destroyed by more than 70%. Levels of FSH were not significantly different from those of control or sham-lesioned groups. Lesions that were dorsal, ventral or caudal to the A13 DA systems did not affect the preovulatory surges of LH and prolactin whereas anterior lesions caused variable changes in the level of all three hormones. These data suggest that the A13 DA region may have a role in the control of the preovulatory surges of LH and prolactin.

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Section: Discussionmentioning

confidence: 99%

Effect of Medial Zona Incerta Lesions on the Ovulatory Surge of Gonadotrophins and Prolactin in the Rat

Sanghera¹,

Anselmo-Franci²,

McCann³

1991

Neuroendocrinology

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“…However, of these three schemes, 3 is the most compelling (Fink, 1988 a, b) here. First, the inhibitory action of dopamine on LHRH-LH release was first suggested by Fuxe & H6kfelt (1970) and later by Lofstr6m, Agnati, Fuxe & H6kfelt (1977) on the basis of measurement of catecholamine turnover in the median eminence. These findings are supported by direct evidence from our studies in which we investigated the effect of pharmacological manipulation of catecholamines on the LHRH surge induced in immature rats by administering pregnant mare serum gonadotrophin (PMSG).…”

Section: Rapid Effects Of Steroidsmentioning

confidence: 99%

The G. W. Harris Lecture Steroid Control of Brain and Pituitary Function

Fink

1988

Exp Physiol

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“…Furthermore, upon TH inhibition a clearly significant lowering of LH serum levels was also demonstrated in these nicotine-treated female rats. These results may be explained on the basis of an increased dependency on release of CA from adrenaline and NA nerve terminal systems of the hypothalamus and preoptic area known to have a stimulatory role in the control of serum TSH and LH levels (12,(18)(19)(20)(21)(22)(23)(24). This increase in the dependency of stimulatory NA and adrenaline networks may be related to the increase in DA utilization in the tubero-infundibular DA neurons, which exhibit inhibitory effects on serum TSH, prolactin and LH levels.…”

Section: Discussionmentioning

confidence: 99%

Effects of Combined Pre‐ and Postnatal Treatment with Nicotine on Hypothalamic Catecholamine Nerve Terminal Systems and Neuroendocrine Function in the 4‐Week Old and Adult Male and Female Diestrous Rat

Jansson

Andersson

Fuxé

et al. 1989

J Neuroendocrinology

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Male and female Sprague-Dawley rats were treated with nicotine during the prenatal period and the first three postnatal weeks (the pregnant and lactating rats were given nicotine hydrogen ( + ) tartrate (165 mg/l) in the tap water). Catecholamine fluorescence was evaluated using quantitative histofluorometry on brain sections treated according to Falck-Hillarp methodology. In order to evaluate catecholamine utilization in discrete hypothalamic catecholamine nerve terminal networks, the aMT-(a-methyl-( f)-p-tyrosine methyl ester) induced catecholamine disappearance was studied 2 h following the tyrosine hydroxylase inhibition. The body weight was reduced in both the male and female rats from 3 weeks of age until 9 weeks of age following pre-and postnatal treatment with nicotine.Following one week of withdrawal from pre-and postnatal treatment with nicotine, an increased catecholamine utilization was observed in the medial and lateral palisade zones of the median eminence mainly in the female rat. In the female rat, reduced prolactin serum levels were found both in the presence and absence of aMT treatment as well as reduced luteinizing hormone concentration in the presence of aMT treatment.At 6 months of age indications of a maintained, weak activation of the catecholamine nerve terminal systems in the medial palisade zones of the median eminence were observed in male rats pre-and postnatally treated with nicotine. Furthermore, increased noradrenaline levels were found in the paraventricular hypothalamic nucleus. An increase in serum luteinizing hormone levels was also found in these rats. In the 7-month old diestrous rat, maintained marked increases in catecholamine utilization in the medial and lateral palisade zones of the median eminence were found following treatment with nicotine during the pre-and postnatal period. A significant reduction of nigral dopamine stores was also demonstrated. The serum levels of thyroid stimulating hormone, prolactin and luteinizing hormone were unchanged in these rats both in the presence and absence of tyrosine hydroxylase inhibition. Finally, pre-and postnatal treatment with nicotine did not alter 13H]nicotine binding (quantitative receptor autoradiography) in cortical, striatal and thalamic areas of the adult diestrous rat.The results demonstrate that pre-and postnatal treatment with nicotine in the drinking water produces permanent activations of the catecholamine nerve terminal networks of the external layer of the median eminence mainly in the female rat. These changes appear to be associated with reduced serum prolactin levels in the 4-week old female rat. Sex-specific changes occur in discrete noradrenaline nerve terminal systems. The observed changes may have functional consequences for neuroendocrine regulation and for the regulation of food and water intake as well as sex-specific responses to stress in the male versus the female rat. Nicotine-induced disturbances in brain cell replication and differentiation may underlie the permanent alteration found in dis...

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Evidence for an Inhibitory Dopaminergic and Stimulatory Noradrenergic Hypothalamic Influence on PMS-Induced Ovulation in the Immature Rat. II. A Pharmacological Analysis

Cited by 16 publications

References 14 publications

Effect of Medial Zona Incerta Lesions on the Ovulatory Surge of Gonadotrophins and Prolactin in the Rat

Effect of Medial Zona Incerta Lesions on the Ovulatory Surge of Gonadotrophins and Prolactin in the Rat

The G. W. Harris Lecture Steroid Control of Brain and Pituitary Function

Effects of Combined Pre‐ and Postnatal Treatment with Nicotine on Hypothalamic Catecholamine Nerve Terminal Systems and Neuroendocrine Function in the 4‐Week Old and Adult Male and Female Diestrous Rat

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