Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1995 Nov 1;488(Pt 3):701–708. doi: 10.1113/jphysiol.1995.sp021001

Electrophysiological differences between oxytocin and vasopressin neurones recorded from female rats in vitro.

J E Stern 1, W E Armstrong 1
PMCID: PMC1156735  PMID: 8576859

Abstract

1. Intracellular recordings in vitro from immunochemically identified oxytocin (OT) and vasopressin (VP) neurones in the supraoptic nucleus (SON) of virgin or lactating female rats revealed no differences between neurone types in membrane potential (Vm), input resistance and current-voltage relationships (I-V), when taken at resting membrane potentials. 2. When OT (94%), but not VP, neurones (93%) were current clamped at depolarized voltages (above -50 mV), small hyperpolarizing pulses revealed a time- and voltage-dependent outward rectification that was present above -75 mV and that decreased in amplitude as Vm approached the equilibrium potential for potassium (EK). The rectification was more pronounced when the neurones were held at a more depolarized membrane potential, and was larger the longer the neurone was held depolarized, reaching a maximum at 0.6-0.9 s. 3. A rebound depolarization followed the offset of hyperpolarizing pulses that were associated with the rectification. The peak amplitude of the rebound showed a time and a voltage dependence. It followed a bell-shaped curve as the hyperpolarizing commands were made larger, attaining a peak at -65 +/- 1.5 mV. The rebound amplitude increased with pulse duration, achieving a half-maximal amplitude at 0.5 +/- 0.1 s. 4. The expression of the sustained outward rectification and the rebound in OT neurones was similar in virgin and lactating female rats. 5. These results indicate the presence of significant differences in the intrinsic membrane properties, probably K+ currents, between OT and VP neurones in both lactating and virgin female rats.

Full text

PDF
701

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Adams P. R., Brown D. A., Constanti A. M-currents and other potassium currents in bullfrog sympathetic neurones. J Physiol. 1982 Sep;330:537–572. doi: 10.1113/jphysiol.1982.sp014357. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Andrew R. D., Dudek F. E. Burst discharge in mammalian neuroendocrine cells involves an intrinsic regenerative mechanism. Science. 1983 Sep 9;221(4615):1050–1052. doi: 10.1126/science.6879204. [DOI] [PubMed] [Google Scholar]
  3. Andrew R. D., Dudek F. E. Intrinsic inhibition in magnocellular neuroendocrine cells of rat hypothalamus. J Physiol. 1984 Aug;353:171–185. doi: 10.1113/jphysiol.1984.sp015330. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Armstrong W. E., Sladek C. D. Evidence for excitatory actions of histamine on supraoptic neurons in vitro: mediation by an H1-type receptor. Neuroscience. 1985 Oct;16(2):307–322. doi: 10.1016/0306-4522(85)90004-1. [DOI] [PubMed] [Google Scholar]
  5. Bourque C. W. Ionic basis for the intrinsic activation of rat supraoptic neurones by hyperosmotic stimuli. J Physiol. 1989 Oct;417:263–277. doi: 10.1113/jphysiol.1989.sp017800. [DOI] [PMC free article] [PubMed] [Google Scholar]
  6. Brimble M. J., Dyball R. E. Characterization of the responses of oxytocin- and vasopressin-secreting neurones in the supraoptic nucleus to osmotic stimulation. J Physiol. 1977 Sep;271(1):253–271. doi: 10.1113/jphysiol.1977.sp011999. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Kita H., Armstrong W. A biotin-containing compound N-(2-aminoethyl)biotinamide for intracellular labeling and neuronal tracing studies: comparison with biocytin. J Neurosci Methods. 1991 Apr;37(2):141–150. doi: 10.1016/0165-0270(91)90124-i. [DOI] [PubMed] [Google Scholar]
  8. Lincoln D. W., Wakerley J. B. Electrophysiological evidence for the activation of supraoptic neurones during the release of oxytocin. J Physiol. 1974 Oct;242(2):533–554. doi: 10.1113/jphysiol.1974.sp010722. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Nisenbaum E. S., Wilson C. J. Potassium currents responsible for inward and outward rectification in rat neostriatal spiny projection neurons. J Neurosci. 1995 Jun;15(6):4449–4463. doi: 10.1523/JNEUROSCI.15-06-04449.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Pape H. C., Budde T., Mager R., Kisvárday Z. F. Prevention of Ca(2+)-mediated action potentials in GABAergic local circuit neurones of rat thalamus by a transient K+ current. J Physiol. 1994 Aug 1;478(Pt 3):403–422. doi: 10.1113/jphysiol.1994.sp020261. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Poulain D. A., Wakerley J. B., Dyball R. E. Electrophysiological differentiation of oxytocin- and vasopressin-secreting neurones. Proc R Soc Lond B Biol Sci. 1977 Apr;196(1125):367–384. doi: 10.1098/rspb.1977.0046. [DOI] [PubMed] [Google Scholar]
  12. Rice M. E., Nicholson C. Diffusion characteristics and extracellular volume fraction during normoxia and hypoxia in slices of rat neostriatum. J Neurophysiol. 1991 Feb;65(2):264–272. doi: 10.1152/jn.1991.65.2.264. [DOI] [PubMed] [Google Scholar]
  13. Smith B. N., Armstrong W. E. Tuberal supraoptic neurons--I. Morphological and electrophysiological characteristics observed with intracellular recording and biocytin filling in vitro. Neuroscience. 1990;38(2):469–483. doi: 10.1016/0306-4522(90)90043-4. [DOI] [PubMed] [Google Scholar]
  14. Wakerley J. B., Poulain D. A., Brown D. Comparison of firing patterns in oxytocin- and vasopressin-releasing neurones during progressive dehydration. Brain Res. 1978 Jun 16;148(2):425–440. doi: 10.1016/0006-8993(78)90730-8. [DOI] [PubMed] [Google Scholar]
  15. Yamashita H., Inenaga K., Kawata M., Sano Y. Phasically firing neurons in the supraoptic nucleus of the rat hypothalamus: immunocytochemical and electrophysiological studies. Neurosci Lett. 1983 May 27;37(1):87–92. doi: 10.1016/0304-3940(83)90509-8. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES