Abstract
In order to ascertain if prolactin (PRL) secretion stimulated by serotonin (5-HT) was mediated by the dopaminergic system, both dopamine (DA) and 5-HT were infused into the third ventricle of anesthetized laying turkeys in conjunction with the D1 DA receptor antagonist R(+)-SCH-23390 HCI or the 5-HT receptor antagonist Mianserin HCl. When infused alone at the rate of 10 nmol/min, both DA and 5-HT increased circulating PRL levels significantly (P < 0.05) after 20 min (111.0 ± 19.0 to 334.0 ± 115.1 ng/ml and 93.3 ± 13.2 to 173.8 ± 33.3 ng/ml, respectively). When infused in conjunction with the D1 DA antagonist, the stimulatory effect of both DA and 5-HT on PRL release was significantly suppressed. The 5-HT antagonist completely blocked 5-HT- stimulated PRL release when infused at the rate of 10 nmol/min. When the 5- HT antagonist was co-infused with DA, PRL levels significantly increased (33.5 ± 3.3 to 112.2 ± 19.7 ng/ml) after 30 min, an increase that did not differ significantly from that caused by DA alone (63.2 ± 16.4 to 144.5 ± 44.1 ng/ml). These data suggest that 5-HT stimulation of PRL secretion requires an intact dopaminergic system and that 5-HT synapses are located further upstream than DA synapses along the PRL-releasing pathway within the avian hypothalamus.
Original language | English (US) |
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Pages (from-to) | 63-68 |
Number of pages | 6 |
Journal | General and Comparative Endocrinology |
Volume | 112 |
Issue number | 1 |
DOIs | |
State | Published - Oct 1998 |
Bibliographical note
Funding Information:This is Scientific Journal Series Paper 981168604 of the Minnesota Agriculture Experiment Station. Research supported by USDA Grant No. 97–35203–4960.
Keywords
- Birds
- Dopamine
- Prolactin
- Serotonin
- Vasoactive intestinal peptide