Elsevier

Neuroscience

Volume 132, Issue 3, 2005, Pages 755-766
Neuroscience

Co-localization and distribution of corticotrophin-releasing hormone, arginine vasopressin and enkephalin in the paraventricular nucleus of sheep: A sex comparison

https://doi.org/10.1016/j.neuroscience.2005.01.045Get rights and content

Abstract

The paraventricular nucleus (PVN) is integral to regulation of the hypothalamo-pituitary-adrenal (HPA) axis and contains cells producing corticotrophin-releasing hormone (CRH), arginine vasopressin (AVP) and enkephalin. We used immunohistochemistry to map these peptides and to resolve the extent of co-localization within PVN cells in intact and gonadectomized male and female sheep. Immunoreactive (ir) CRH, AVP and enkephalin cells were mapped in two rams and two ewes at 180 μm intervals throughout the rostro-caudal extent of the PVN. Similar distributions of AVP-ir cells occurred in both sexes whereas CRH-ir and enkephalin-ir cells extended more rostrally in rams. In groups (n=4) of intact and gonadectomized sheep of both sexes, co-localization and distribution of neuropeptides was influenced by sex and gonadectomy. Males had more AVP and CRH cells than females. Intact animals had more AVP cells than gonadectomized animals. There were no differences between groups in the number or percentage of cells that stained for both CRH and AVP or in the number of cells that stained for both CRH and enkephalin. Differences were observed in the percentage of enkephalin cells that contained CRH with males having a greater percentage of co-localized cells than did females. Differences were also observed in the number and percentage of cells that stained for both enkephalin and AVP; the number of cells that stained for both neuropeptides was greater in males than in females and greater in intact animals than in gonadectomized animals. Differences were observed in the percentage of AVP cells that contained enkephalin, and in the percentage of enkephalin cells that contained AVP with males having a greater percentage of co-localized cells than did females. We conclude that sex and gonadal status affect peptide distribution in the PVN of the sheep which may provide an anatomical basis for sex differences in HPA axis responses to stress.

Section snippets

Animals and tissue collection

Adult male and female Corriedale sheep were used. Experiment 1 (co-localization of neuropeptides) used both gonadectomized and intact male and female sheep (n=4/group). Experiment 2 (distribution of neuropeptides) used intact male and female sheep (n=2/group). The animals had been gonadectomized at least 2 weeks prior to tissue collection and kept under normal conditions at the Prince Henry’s Institute of Medical Research experimental facility (Clayton, Victoria, Australia; 38° latitude). All

Experiment 1 (co-localization of neuropeptides)

The standard error of the mean (±S.E.M.) number of cells staining for CRH, AVP and ENK in intact and gonadectomized rams and ewes in the PVN is represented in Fig. 1, Fig. 2, Fig. 3. Fig. 1 presents data for single labeling. Fig. 2 (double labeling) represents the mean number of cells staining for CRH/AVP, AVP/ENK and CRH/ENK in intact and gonadectomized rams and ewes. All data presented in Fig. 2 are untransformed. Nevertheless, the data in Fig. 2c were log transformed for statistical analysis

Discussion

We have found differences in the distribution of cells that produce CRH, AVP and ENK and differences in the co-localization of these peptides within the PVN of male and female sheep. In some instances, the presence or absence of the gonads influenced the co-localization of these neuropeptides. We observed sex differences in the distribution of CRH and ENK cells and in the co-localization of AVP/ENK and CRH/ENK. Although there are some reports on the distribution and co-localization of these

Acknowledgments

We thank Bruce Doughton, Karen Briscoe, Lynda Morris, Alda Perreira, Sueli Pompolo, Chris Scott and Michelle Ibbot for technical assistance. We would like to thank Prof. W. Vale for his generous gift of the CRH antibody and Prof. H. Gainer who kindly donated both the monoclonal and polyclonal AVP antibodies. This research was funded by the National Health and Medical Research Council of Australia and Monash University.

References (63)

  • L. Marson et al.

    Immunohistochemical distribution of cholecystokinin, dynorphin A and Met-enkephalin neurons in sheep hypothalamus

    Neurosci Lett

    (1987)
  • W. Paull et al.

    Immunocytochemical localization of CRF in the ovine hypothalamus

    Peptides

    (1982)
  • M.E. Rhodes et al.

    Functional sex differences (‘sexual diergism’) of central nervous system cholinergic systems, vasopressin, and hypothalamic-pituitary-adrenal axis activity in mammalsa selective review

    Brain Res Brain Res Rev

    (1999)
  • S.M. Robinson et al.

    Sex differences in the shape of the sexually dimorphic nucleus of the preoptic area and suprachiasmatic nucleus of the rat3-D computer reconstructions and morphometrics

    Brain Res

    (1986)
  • F.W. van Leeuwen et al.

    Vasopressin cells in the bed nucleus of the stria terminalis of the ratsex differences and the influence of androgens

    Brain Res

    (1985)
  • E. Weber et al.

    Levels of pro-neo-endorphin/dynorphin-derived peptides in the hypothalamo-posterior pituitary system of male and female Brattleboro rats

    Brain Res

    (1983)
  • T.R. Akesson et al.

    Endogenous opioid-immunoreactive neurons of the ventromedial hypothalamic nucleus concentrate estrogen in male and female rats

    J Neurosci Res

    (1991)
  • J. Aubry et al.

    Single stress induces long-lasting elevations in vasopressin mRNA levels in CRF hypophysiotrophic neurones, but repeated stress is required to modify AVP immunoreactivity

    J Neuroendocrinol

    (1999)
  • W.J. Bremner et al.

    A study of the reproductive performance of mature Romney and Merino rams throughout the year

  • J. Buckingham et al.

    Interrelationship of opioidergic and adrenergic mechanisms controlling the secretion of corticotrophin releasing factor in the rat

    Neuroendocrinology

    (1987)
  • S. Ceccatelli et al.

    Distribution and co-existence of corticotropin-releasing factor-, neurotensin-, enkephalin-, cholecystokinin-, galanin-, and vasoactive intestinal polypeptide/peptide histidine isoleucine-like peptides in the parvocellular part of the paraventricular nucleus

    Neuroendocrinology

    (1989)
  • S. Ceccatelli et al.

    Effect of different types of stressors on peptide messenger ribonucleic acids in the hypothalamic paraventricular nucleus

    Acta Endocrinol

    (1993)
  • M.D. Chen et al.

    The insulin hypoglycemia-induced inhibition of gonadotropin-releasing hormone pulse generator activity in the rhesus monkeyroles of vasopressin and corticotropin-releasing factor

    Endocrinology

    (1996)
  • J. Corchero et al.

    Gender differences in proenkephalin gene expression response to delta(9)-tetrahydrocannabinol in the hypothalamus of the rat

    J Psychopharmacol

    (2002)
  • D. Engler et al.

    Studies of the secretion of corticotropin-releasing factor and arginine vasopressin into the hypophysial-portal circulation of the conscious sheep: I. Effect of an audiovisual stimulus and insulin-induced hypoglycemia

    Neuroendocrinology

    (1989)
  • M. Familiari et al.

    Arginine vasopressin is a much more potent stimulus to ACTH release from ovine anterior pituitary cells than ovine corticotropin-releasing factor

    Neuroendocrinology

    (1989)
  • L.E. Heisler et al.

    Vasopressin mediates hypoglycemia-induced inhibition of luteinizing hormone secretion in the ovariectomized rhesus monkey

    Neuroendocrinology

    (1994)
  • G.E. Hoffman et al.

    Relationship of endogenous opioid peptide axons to GnRH neurons in the rat

  • J. Kiss et al.

    Corticotropin-releasing factor immunoreactive neurones of the paraventricular nucleus become vasopressin positive after adrenalectomy

    Proc Natl Acad Sci USA

    (1984)
  • S. Lightman et al.

    Changes in hypothalamic pre-proenkephalin A mRNA following stress and opiate withdrawal

    Nature

    (1987)
  • V. Lotti et al.

    Pituitary-adrenal activity following intrahypothalamic microinjections of morphine

    Neuroendocrinology

    (1969)
  • Cited by (21)

    • The vasotocinergic system and its role in the regulation of stress in birds

      2020, Vitamins and Hormones
      Citation Excerpt :

      The mechanisms of sex-dependent responsiveness of the avian HPA axis to stressors are poorly understood. Possible explanations could be the presence of sex differences in AVT- and CRH-expressing neurons (Iwasaki-Sekino, Mano-Otagiri, Ohata, Yamauchi, & Shibasaki, 2009; Jurkevich, Barth, & Grossmann, 1997; Rivalland, Iqbal, Clarke, Turner, & Tilbrook, 2005) and/or distribution of AVT, CRH and glucocorticoid receptors (Dumais & Veenema, 2016; Koch, Wingfield, & Buntin, 2002; Lim, Nair, & Young, 2005). Overall, at the level of the brain, CRH is a more potent stimulator of the HPA axis than AVT in chickens and induces higher levels of CORT in males compared to females.

    • The role of the arginine vasopressin Avp1b receptor in the acute neuroendocrine action of antidepressants

      2008, Psychoneuroendocrinology
      Citation Excerpt :

      Oxt within the PVN appears to inhibit the effect on local Avp release under basal conditions and also to inhibit the ACTH response to acute forced swim stress (Neumann et al., 2006). The lack of fluoxetine effects on Avp, Oxt or Crh mRNA expression in the PVN of males of either genotype also points to gender differences in the regulation of neuropeptide gene expression in the Avpr1b KO and wild-type mice—there is a pronounced sexual dimorphism in the expression of Avp in extra-hypothalamic neuronal fibres (Wang et al., 1993) and there are sex differences in the localisation of neuropeptides and neuronal activation in the PVN (Rivalland et al., 2005; Viau et al., 2005). The question of whether there are gender differences in brain Avpr1b expression is likely to be resolved when selective, high-affinity radiolabelled Avpr1b ligands are developed.

    View all citing articles on Scopus
    View full text