Plasticity in Intrinsic Excitability of Hypothalamic Magnocellular Neurosecretory Neurons in Late-Pregnant and Lactating Rats
| Autor: | Colin H. Brown, Martin Fronius, Michael R. Perkinson, Isaiah Cheong, Gregory T. Bouwer, Alexander J. Seymour, Rachael A. Augustine, Emily F. Brown |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Vasopressin
vasopressin Action Potentials Supraoptic nucleus 0302 clinical medicine Lactation Biology (General) Spectroscopy Neurons Oxytocin secretion General Medicine Computer Science Applications Chemistry medicine.anatomical_structure Vasopressin secretion Basal Nucleus of Meynert supraoptic nucleus Female pregnancy hormones hormone substitutes and hormone antagonists medicine.drug medicine.medical_specialty Vasopressins QH301-705.5 Hypothalamus 030209 endocrinology & metabolism lactation Biology Article Catalysis Inorganic Chemistry 03 medical and health sciences Posterior pituitary Internal medicine oxytocin medicine Animals transient receptor potential vanilloid channel Physical and Theoretical Chemistry Milk Ejection Molecular Biology QD1-999 Organic Chemistry Rats Endocrinology Oxytocin nervous system Neuron 030217 neurology & neurosurgery Paraventricular Hypothalamic Nucleus |
| Zdroj: | International Journal of Molecular Sciences, Vol 22, Iss 7140, p 7140 (2021) International Journal of Molecular Sciences Volume 22 Issue 13 |
| ISSN: | 1661-6596 1422-0067 |
| Popis: | Oxytocin and vasopressin secretion from the posterior pituitary gland are required for normal pregnancy and lactation. Oxytocin secretion is relatively low and constant under basal conditions but becomes pulsatile during birth and lactation to stimulate episodic contraction of the uterus for delivery of the fetus and milk ejection during suckling. Vasopressin secretion is maintained in pregnancy and lactation despite reduced osmolality (the principal stimulus for vasopressin secretion) to increase water retention to cope with the cardiovascular demands of pregnancy and lactation. Oxytocin and vasopressin secretion are determined by the action potential (spike) firing of magnocellular neurosecretory neurons of the hypothalamic supraoptic and paraventricular nucleus. In addition to synaptic input activity, spike firing depends on intrinsic excitability conferred by the suite of channels expressed by the neurons. Therefore, we analysed oxytocin and vasopressin neuron activity in anaesthetised non-pregnant, late-pregnant and lactating rats to test the hypothesis that intrinsic excitability of oxytocin and vasopressin neurons is increased in late pregnancy and lactation to promote oxytocin and vasopressin secretion required for successful pregnancy and lactation. Hazard analysis of spike firing revealed a higher incidence of post-spike hyperexcitability immediately following each spike in oxytocin neurons, but not in vasopressin neurons, in late pregnancy and lactation, which is expected to facilitate high frequency firing during bursts. Despite lower osmolality in late-pregnant and lactating rats, vasopressin neuron activity was not different between non-pregnant, late-pregnant and lactating rats, and blockade of osmosensitive ΔN-TRPV1 channels inhibited vasopressin neurons to a similar extent in non-pregnant, late-pregnant and lactating rats. Furthermore, supraoptic nucleus ΔN-TRPV1 mRNA expression was not different between non-pregnant and late-pregnant rats, suggesting that enhanced activity of ΔN-TRPV1 channels might maintain vasopressin neuron activity to increase water retention during pregnancy and lactation. |
| Databáze: | OpenAIRE |
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