Histamine, a neuromodulator of noradrenergic transmission in uterine horns from mice in diestrus.
The effect of histamine on [3H]norepinephrine ([3H]NE) release in uterine horns from mice in estrous and diestrous states was studied under two different experimental conditions: resting NE release and stimulus-evoked NE release. It was found that [3H]NE release was higher for the diestrous state under both resting and stimulus-evoked (100 mM K+ and electrical stimulus) conditions. Histamine only potentiated the stimulus-evoked [3H]NE outflow in uterine horns from mice in the diestrous state and from ovariectomized mice treated with progesterone. This effect was dose dependent and was antagonized by H1 but not by H2 or H3 antagonists. R-alpha-Methylhistamine, a H3 agonist, has no effect on stimulus-evoked [3H]NE release. According to these results, it could be concluded that: (a) histamine regulates the NE release from noradrenergic nerve terminals in uterine tissues; (b) this heterologous regulation depends on progesterone predominance and on terminal depolarization; and (c) presynaptic H1 receptors located on noradrenergic terminals could be responsible for such an effect.
Montesino
H
H
Departamento de Farmacología, Facultad de Ciencias Biológicas, Universidad de Concepción, Chile.
Villar
M
M
Vega
E
E
Rudolph
M I
MI
D000818:Animals; D004558:Electric Stimulation; D005260:Female; D006632:Histamine / Q000494:pharmacology*; D017442:Histamine Agonists / Q000494:pharmacology; D066298:In Vitro Techniques; D051379:Mice; D009638:Norepinephrine / Q000378:metabolism*; D010052:Ovariectomy; D011188:Potassium / Q000494:pharmacology; D011374:Progesterone / Q000008:administration & dosage; D011968:Receptors, Histamine / Q000187:drug effects; D014590:Uterine Contraction; D014599:Uterus / Q000294:innervation* / Q000378:metabolism
D017442:Histamine Agonists; D011968:Receptors, Histamine; D011374:Progesterone; D006632:Histamine; D011188:Potassium; D009638:Norepinephrine