Plasma Oxytocin During Pregnancy and Lactation in the Cynomolgus Monkey

Morris, Mariana; Stevens, Susan W.; Adams, Michael R.

doi:10.1095/biolreprod23.4.782

Cited by 58 publications

(22 citation statements)

References 21 publications

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“…The slice was sectioned at 16 pm on a cryostat, mounted on Po1)-l-lysine coated slides and stored frozen at a temperature of -20 "C. All of the sections were rinsed in PB and alternate sections were incubated with OT (14) or AVP (15) antisera at 1:1,000 and 1:2,000 dilutions, respectively. Next, the sections were rinsed in PB and reacted for 1 h with a mixture of StWptavidin-FITC diluted 1:600 and IgG conjugated to Texas Red diluted 1:50 (16).…”

Section: Methodsmentioning

confidence: 99%

Inward Rectification (I_h) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Erickson

Rønnekleiv

1990

J Neuroendocrinology

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Intracellular recordings of magnocellular neurons from the supraoptic nucleus of guinea‐pigs were made with KCI/K citrate‐ and biocytin‐filled electrodes. Fifty of 99 cells exhibited a time‐dependent inward rectification (TDR). The TDR was activated during hyperpolarizing current pulses to membrane potentials more hyperpolarized than −75 mV. In voltage‐clamp recordings, an inward current appeared at voltage steps more hyperpolarized than −75 mV, with properties similar to the slow inward rectifier (Ih) described in other tissues. The Ih was blocked by 2 mM CsCI. BaCI2 (100 to 500 μM) did not block the Ih. Immunocytochemical identification of the recorded cells revealed that both vasopressin (AVP)‐ and oxytocin (OT)‐ containing neurons exhibited an Ih.

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Section: Methodsmentioning

confidence: 99%

Inward Rectification (I_h) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Erickson

Rønnekleiv

1990

J Neuroendocrinology

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“…By convention, perfusate data time points correspond to the end of the collection intervals. AVP and OT were measured by specific and sensitive radioimmunoassays as previously described (15,17]. Crossreactiv ity of the AVP and OT antisera with OT and AVP, respectively, or vasotocin was < 0.1%.…”

Section: Methodsmentioning

confidence: 99%

Osmotic Mechanisms Regulating Cerebrospinal Fluid Vasopressin and Oxytocin in the Conscious Rat

Morris¹,

Barnard²,

Sain³

1984

Neuroendocrinology

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The effect of intraventricular and intravenous (i.v.) hypertonic saline on plasma and perfusate arginine vasopressin (AVP) and oxytocin (OT) levels was determined. A push-pull technique was used to sample third ventricular cerebrospinal fluid (CSF) in the conscious unrestrained rat. Intraventricular perfusion of hypertonic saline caused a 6.1-and 4.2-fold increase in perfusate levels of AVP and OT. Plasma levels with the same stimulus increased 3.5-fold for AVP and 3.4-fold for OT. Peak levels of the peptides occurred at 30 and 60 min in the CSF perfusate and plasma, respectively. Thus, the central peptide response occurred earlier and was of a greater magnitude than the systemic one. Intravenous hypertonic saline administration caused a rapid (15 min) increase in plasma AVP and OT, changes of 12.6- and 22.9-fold. Perfusate AVP did not change with i.v. hypertonic saline while OT was increased 10-fold. Two types of recovery experiments were performed (1) in which the rate of disappearance of ¹²⁵I-labeled peptides from CSF was determined and (2) in which total body water was labeled with ³H₂O and the amount of dilution determined. Both techniques showed that recovery of endogenous CSF in the push-pull perfusate was approximately 15%. Thus, the perfusate peptide levels represent an underestimation of in vivo secretion. Osmotic stimuli elicit specific changes in the third ventricular levels of AVP and OT. The differential response in the two hormones to i.v. hypertonic saline shows a uniqueness in the mechanisms controlling the central secretion of AVP and OT.

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“…Alternate sections were incubated with OT (Morris, Stevens & Adams, 1980) or AVP (Dave, Rubinstein & Eskay, 1985) antisera at 1: 1000 and 1:2000 dilutions, respectively, for 16-32 h. The antisera for each hormone (AVP and OT) showed no crossreactivity with the other hormone. For evaluation of the specificity of the immunocytochemical reactions, some of the tissue sections were reacted with AVP and OT antisera that had been incubated for 24 h with synthetic AVP and OT, respectively (each 7 5 ,tg/ml).…”

Section: Immunocytochemical Identificationmentioning

confidence: 99%

Electrophysiology of guinea‐pig supraoptic neurones: role of a hyperpolarization‐activated cation current in phasic firing.

Erickson

Rønnekleiv

Kelly

1993

The Journal of Physiology

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SUMMARY1. Immunocytochemically identified magnocellular neurosecretory cells (MNCs) in the guinea-pig supraoptic nucleus (SON) were studied using the in vitro intracellular recording technique. Cells were identified as containing arginine vasopressin (AVP) or oxytocin (OT) following recordings made with biocytin-filled electrodes. Both AVP and OT MNCs demonstrated a fusiform or pyramidal shape (15-20 jtm by 26-39,tm), with two to three processes. There were no significant differences in the proportion of AVP and OT cells in the retrochiasmatic (caudal) versus the rostral slices.2. No significant differences in passive membrane properties were observed between AVP and OT cells, except that AVP cells exhibited a significantly broader action potential width (I51+041 ms, n = 11) than did OT cells (IOl +0-08 ms, n = 7).3. Firing patterns were recorded for 100 MNCs, 41 % of which fired in a phasic manner (repeated clustering of action potentials into bursts). Of the seventy-seven cells which were immunocytochemically identified, only AVP-containing MNCs displayed phasic firing. Phasic firing occurred only in MNCs demonstrating a depolarizing potential which followed hyperpolarizing after-potentials (HAPs). The presence of the depolarizing potential was not always associated with phasic firing, however, as both OT cells and non-phasic AVP cells sometimes exhibited a depolarizing potential.4. In 160 MNCs examined for the presence of the time-dependent inward rectification (TDR in current clamp, or Ih in voltage clamp), a significant difference in the proportion of cells expressing the Ih was observed in the two cell types. The was expressed in forty-five of fifty-four AVP MNCs (83 %) and in six of fifteen OT MNCs (40%). No significant association was found with firing pattern.5. The Ih exhibited properties similar to those found in other CNS and peripheral tissues. It appeared on steps to potentials more hyperpolarized than -65 mV. It was augmented by raising the extracellular potassium concentration, blocked by 2 mm CsCl, and insensitive to 100-500 /AM BaCl2. Activation followed a single exponential, and the time constant of activation was voltage dependent.6. The adenylate cyclase activator forskolin increased the Ih and shifted its

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Plasma Oxytocin During Pregnancy and Lactation in the Cynomolgus Monkey

Abstract: Plasma levels of oxytocin were measured during pregnancy and lactation in a group (n = 23) of cynomolgus monkeys (Ma coca fascicularis).

Cited by 58 publications

References 21 publications

Inward Rectification (I_h) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Inward Rectification (I_h) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Osmotic Mechanisms Regulating Cerebrospinal Fluid Vasopressin and Oxytocin in the Conscious Rat

Electrophysiology of guinea‐pig supraoptic neurones: role of a hyperpolarization‐activated cation current in phasic firing.

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Plasma Oxytocin During Pregnancy and Lactation in the Cynomolgus Monkey

Abstract: Plasma levels of oxytocin were measured during pregnancy and lactation in a group (n = 23) of cynomolgus monkeys (Ma coca fascicularis).

Cited by 58 publications

References 21 publications

Inward Rectification (Ih) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Inward Rectification (Ih) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Osmotic Mechanisms Regulating Cerebrospinal Fluid Vasopressin and Oxytocin in the Conscious Rat

Electrophysiology of guinea‐pig supraoptic neurones: role of a hyperpolarization‐activated cation current in phasic firing.

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Product

Resources

About

Inward Rectification (I_h) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus

Inward Rectification (I_h) in Immunocytochemically‐ldentified Vasopressin and Oxytocin Neurons of Guinea‐Pig Supraoptic Nucleus