Biomedical subjects

J Vega-Matuszczyk

Publications and source records attributed to J Vega-Matuszczyk.

4 recordsLinked to original sources

PubMed1996

The effects of lesions in the mesencephalic raphe systems on male rat sexual behavior and locomotor activity.

Lesions were produced in the median and the dorsal raphe nuclei of the rat, and the effects of these injuries on various behaviors were studied. The median raphe lesions had facilitatory effects on the male rat sexual behavior, as evidenced by a decrease in the number of intromissions prior to ejaculation, as well as shortening of the ejaculation latency and the postejaculatory interval. No effects were seen on the masculine sexual behavior after lesions in the dorsal raphe nucleus. The median raphe lesions drastically increased the locomotory activity whereas the dorsal raphe lesions did not. Treatment with FG5893, a 5-HT1A agonist/5-HT2A receptor antagonist, increased the locomotor activity of the dorsal-raphe-lesioned rats but did not affect the median-raphe-lesioned animals. These results suggest that the dorsal and the median raphe nuclei play different roles in the neural regulation of the sexual behavior and locomotor activity of the male rat. The median raphe nucleus appears to exert a modulatory influence upon these behaviors, which probably is mediated by serotonergic neural pathways.

Animals↗

PubMed1995

Adrenalectomy does not prevent the ability of 8-OH-DPAT to decrease the ejaculatory threshold in male rats.

The present experiments demonstrate that 8-OH-DPAT (0.25 mg/kg SC, - 15 min) produced a decrease in the ejaculatory threshold to the same extent in adrenalectomized male rats as in sham operated controls. Both groups of animals displayed a marked and statistically significant decrease in number of mounts and penile intromissions preceding ejaculation and in the ejaculation latency, as a result of treatment with 8-OH-DPAT. Adrenalectomy per se did not affect any aspect of the male rat's sexual behavior (latency to first intromission, number of mounts or penile intromissions, ejaculation latency or the postejaculatory interval). The surgical removal of the adrenals was verified by measurements of plasma corticosterone levels. It is concluded that well documented effects of 8-OH-DPAT on adrenal secretions do not contribute to its ability to decrease the ejaculatory threshold in male rats.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

PubMed1993

Effects of exposure to an estrous female on forebrain monoaminergic neurotransmission in the non-copulating male rat.

Regional changes in the rate of brain monoamine synthesis were monitored in male rats exposed to, but prevented from physical contact with, an estrous or an ovariectomized female. The in vivo rate of tyrosine and tryptophan hydroxylase activities were estimated by measuring the accumulation of DOPA and 5-HTP following inhibition of cerebral aromatic L-amino acid decarboxylase by means of 3-hydroxybenzylhydrazine (NSD-1015) treatment (100 mg/kg i.p.). 5 min upon NSD-1015 treatment, the males were exposed to an intact estrous female or an ovariectomized female for 20 min before decapitation and brain dissections. Exposure to an estrous female produced an increased rate of tyrosine and tryptophan hydroxylase activity in the medial prefrontal cortex, the dorso-lateral neostriatum and in the ventral neostriatum, in comparison with home-cage controls. By the same comparison, exposure to an ovariectomized female resulted in an increased rate of tyrosine hydroxylase activity in the medial prefrontal cortex, but not in the neostriatal areas, whereas tryptophan hydroxylase activity was unaffected. Finally, exposure to the empty test cage, with no stimulus females present, did not produce any statistically significant changes in the rate of tyrosine or tryptophan hydroxylase activity in any of the brain areas sampled. Taken together with recent findings from this laboratory, the present results demonstrate that the level of sexual motivation brought about by the olfactory, auditory and/or visual stimulation of a receptive female is associated with an increased demand on catecholamine and 5-hydroxytryptamine synthesis in the limbic forebrain of the male rat.(ABSTRACT TRUNCATED AT 250 WORDS)

Acoustic Stimulation↗

PubMed1991

Synergistic action of estradiol, progesterone and testosterone on rat proceptive behavior.

The role of estradiol (E), progesterone (P) and testosterone (T) in the control of rat feminine sexual behavior (receptivity, proceptivity and sexual orientation) was analyzed. The action of estradiol benzoate (EB, 1.25 micrograms/rat x 3 days) and P (0.5 mg/rat) was compared in ovariectomized (OVX) and ovariectomized-adrenalectomized (OVX + ADX) subjects. Administration of EB alone was followed by maximum levels of lordosis behavior and a male-directed orientation in both OVX and OVX + ADX females. A reduction in the level of proceptivity was observed in EB-treated OVX + ADX animals as compared with EB-treated OVX rats. The administration of P to OVX + ADX females resulted in an increase in proceptive behavior similar to that observed in OVX EB-treated animals. A further study analyzed the effect of combined administration of EB, P and various doses of T (30, 90 and 270 micrograms/rat) in OVX + ADX rats. A synergistic action of all three hormones on proceptivity was observed. Neither a further increase in lordosis nor in male-directed orientation was observed in EB-treated females after additional treatment with P or T independently or together. Finally, we studied the effect of adrenalectomy on the spontaneous onset of estrous behavior. Adrenalectomy did not modify any aspect of normal feminine sexual behavior, suggesting that the adrenals, in the presence of the ovaries, are of no critical importance for this behavior. The possible contribution of adrenal steroids to the expression of proceptivity is discussed.

Adrenalectomy↗