EFFECTS OF CHOUNOCEPTOR ANTAGONISTS ON THE SUCKLING‐INDUCED AND EXPERIMENTALLY EVOKED RELEASE OF OXYTOCIN

@article{Clarke1978EFFECTSOC,
  title={EFFECTS OF CHOUNOCEPTOR ANTAGONISTS ON THE SUCKLING‐INDUCED AND EXPERIMENTALLY EVOKED RELEASE OF OXYTOCIN},
  author={G. Clarke and Caroline H. D. Fall and Dennis W. Lincoln and LYNDA P. Merrick},
  journal={British Journal of Pharmacology},
  year={1978},
  volume={63}
}
1 In the anaesthetized lactating rat, the suckling of the young causes the regular release (about every 7 min) of brief pulses of oxytocin (0.5 to 1.0 mu), which each produce a single transient increase in intramammary pressure. 2 The effects of several cholinoceptor antagonists were studied in relation to this natural reflex, and also the release of oxytocin evoked by the intraventricular injection of cholinomimetics. 3 Reflex milk ejection was blocked by the nicotinic antagonists mecamylamine… 

A comparison of analgesia and suppression of oxytocin release by opiates

The results obtained with lactating rats suggest that secretion of the hormone oxytocin is substantially reduced during opiate‐induced analgesia.

Central inhibitory effects of muscimol and bicuculline on the milk ejection reflex in the anaesthetized rat.

The powerful inhibitory action on the milk ejection reflex of both muscimol and bicuculline provides evidence for the importance of GABA neurones in maintaining the functional integrity of the mechanisms which allow the intermittent and pulsatile release of oxytocin during suckling.

Relaxin affects the central control of oxytocin release

It is reported that reflex milk ejection was suppressed by relaxin in a dose-dependent manner, the onset of inhibition being rapid and lasting from 10 to 60 min, and a novel role for relaxin within the central nervous system is suggested.

Regulation of Oxytocin Release

As with most hormones, understanding of the mechanisms of release has depended on the availability of sensitive assay techniques and the number of samples which can be processed is very limited.

Naloxone excites oxytocin neurones in the supraoptic nucleus of lactating rats after chronic morphine treatment.

Tolerance to initial inhibitory effects of morphine on oxytocin secretion is indicated, and the excitatory effects of naloxone on neurones in the supraoptic nucleus of morphine‐treated rats were not explained by changes in blood pressure or osmolarity and did not depend on suckling or a cholinergic pathway.

A cholinergic link in the reflex release of vasopressin by hypotension in the rat.

The results show that the antidiuretic response to the hypotension induced by amyl nitrite is due to the release of vasopressin and that this release is mediated by a neuroendocrine reflex acting through the brain stem.

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