Postnatal Treatment of Rats with Beta-adrenergic Agonists or Antagonists Influences Differentiation of Sexual Brain Functions^*)

Abstract

Sexual differentiation of the brain seems to be influenced by postnatal interaction of gonadal steroids with neurotransmitter systems, in particular the adrenergic system. Stimulation or inhibition of alpha-adrenergic receptors during early postnatal development had previously been shown to influence steroid-induced sexual differentiation of brain functions. In the present study newborn male and female rats were treated either with salbutamol, a selective beta 2-adrenergic receptor agonist, isoprenaline, a general beta-adrenergic receptor agonist, or with alprenolol, a general beta-adrenergic receptor antagonist. In adulthood the female animals were ovariectomized and were tested for the capacity to show an LH-surge response and female sexual behaviour after priming with estradiol benzoate (EB) and progesterone (P). Male animals were tested for expression of male sexual behavior and, after gonadectomy and priming with EB + P, for the capacity to show female lordosis behavior. In summary, our results suggest that activation or inhibition of beta-adrenergic receptors during postnatal development permanently impairs the responsiveness of the center for cyclic gonadotropin release to gonadal steroids in female rats and impairs the expression of ejaculatory behavior in male rats. A slight stimulatory effect on the expression of female lordosis behavior was observed in male and female rats after postnatal activation of beta-adrenergic receptors.

Influence of a Dopamine Agonist (Lisuride) on Sex-Specific Behavioural Patterns in Rats. II. Long-Term Effects*)

“…Sexual orientation of castrated females even under androgen stimulation is predominantly homotypical, i.e., these females show more receptive than mounting behaviour, although in our experiment the number of positive tests with lordotic behaviour were unexpectedly low. Jarzab et al (1989) described similar low levels of lordosis in normal female rats and suspected the existence of circannual differences. Early postnatal as well as peripuberal lisuride administration led to a permanent conversion of this behavioural pattern.…”

Short- and Long-term Effects of a Dopamine Agonist (Lisuride) on Sex-specific Behavioural Patterns in Rats

“…these females show more receptive than mounting behaviour, although in our experiment the number of tests with lordoses was unexpectedly low. However, Jarzab et al (1989) described similar low levels of lordotic behaviour in normal female rats and suspected circannual differences to be responsible. Early postnatal as well as peripuberal lisuride administration led to a permanent conversion of this behavioural pattern.…”

“…Early postnatal application of neurodrugs had also permanent effects on sexual functions (Dörner et al, 1976b;Tönjes et al, 1981). Different neurotransmitter systems have been suggested to participate in steroiddependent sexual differentiation of the brain (Ladosky and Gaziri, 1970;Dörner, 1976a;1980;Raum et al, 1984;Reznikov, 1986;Jarzab et al, 1989). According to Döcke et al (1987) central dopaminergic systems are implicated in the estrogeninduced desensitization of LH secretion to the negative estrogen feedback.…”

Φυλετικοί Και Αναπτυξιακοί Μηχανισμοί Πλαστικότητας Στον Εγκέφαλο Ερμαφρόδιτων Τελεόστεων. Μελέτη Της Έκφρασης Νοραδρενεργικών Υποδοχέων Και Της Γένεσης Και Μετανάστευσης Κυττάρων

“…Τις τελευταίες τέσσερις δεκαετίες έχει συγκεντρωθεί ένας διόλου ευκαταφρόνητος όγκος πληροφοριών σχετικά µε τη λειτουργία του νοραδρενεργικού συστήµατος και την κατανοµή των υποδοχέων του στον εγκέφαλο των ενήλικων σπονδυλωτών, ελάχιστα είναι γνωστά για τη µετεµβρυϊκή ανάπτυξη του. Μελέτες σε θηλαστικά (Flügge et al 1993a, Hamilton et al 1984) και σε πτηνά (Revilla et al 1998) Orensaz et al 1982, Jarzab et al 1989, Paulose and Kanungo 1982, Ball et al 1989, Riters et al 2002.…”