HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by CLARKE, G. Articles by MERRICK, L. P. Search for Related Content PubMed PubMed Citation Articles by CLARKE, G. Articles by MERRICK, L. P.

During suckling, anaesthetized lactating rats release regular (about every 7 min) but brief )ulses of oxytocin (0·5–1·0 mu.) which produce single transient increases in intramammary [unk]ressure. Drugs which selectively impair synaptic transmission were used to determine the [unk]ole of dopamine and noradrenaline in regulating this natural reflex. Diethyldithiocarbamate 100–200 mg/kg, i.v.) and -methylparatyrosine (100–400 mg/kg, i.v.) which inhibit the [unk]ynthesis of catecholamines both blocked the suckling-induced release of oxytocin. The milk[unk]jection reflex was also inhibited in a dose-dependent manner by the intravenous administraion of the dopamine antagonists, fluphenazine (0·7 mg/kg), pimozide (1·4 mg/kg), cis-lupenthixol (4·5 mg/kg) and metoclopramide (6·0 mg/kg), and caused a significant inhibition P < 0·01) of the reflex in 50% of the rats tested. The -adrenoceptor antagonist phenoxy[unk]enzamine (1·4 mg/kg) was similarly effective. Dopamine (40 µg), bromocriptine (10 µg), [unk]pomorphine (100 µg), noradrenaline (10 µg) and phenylephrine (2 µg) injected into the;erebral ventricles evoked a sustained release of oxytocin which produced multiple increases n intramammary pressure; isoprenaline (4 µg) was ineffective. The release of oxytocin evoked [unk]y dopamine and noradrenaline was prevented by cis-flupenthixol and phenoxybenzamine respectively. None of the drugs used affected the mammary sensitivity to exogenous oxytocin lor were their actions modified by pretreatment with propranolol (1 mg/kg). The results [unk]uggest that the neural pathway for the reflex release of oxytocin during suckling in the rat [unk]ontains both dopaminergic and noradrenergic synapses, the latter acting through -[unk]drenoceptors and being distal in the pathway to the dopaminergic component.

This article has been cited by other articles:

				F. A. Champagne, P. Chretien, C. W. Stevenson, T. Y. Zhang, A. Gratton, and M. J. Meaney Variations in Nucleus Accumbens Dopamine Associated with Individual Differences in Maternal Behavior in the Rat J. Neurosci., April 28, 2004; 24(17): 4113 - 4123. [Abstract] [Full Text] [PDF]

				S. L. Bealer and W. R. Crowley Noradrenergic control of central oxytocin release during lactation in rats Am J Physiol Endocrinol Metab, March 1, 1998; 274(3): E453 - E458. [Abstract] [Full Text] [PDF]