Biomedical subjects

M Carro-Juárez

Publications and source records attributed to M Carro-Juárez.

7 recordsLinked to original sources

PubMed2006

Evidence for the presence of the spinal pattern generator involved in the control of the genital ejaculatory pattern in the female rat.

Substantial progress has been made during recent years in elucidating the control of male ejaculatory function by the central nervous system. These efforts have revealed the participation of a central pattern generator in the control of ejaculation. There is a strong similarity in the neural organization of male and female sexual functions. In the present study, the hypothesis that the spinal generator for ejaculation was present and functional in the female rat was evaluated. To this purpose, the expression of the ejaculatory motor pattern and its pharmacological activation in spinally transected female rats were investigated. Results revealed the presence in females of the already described rhythmic ejaculatory motor pattern of male rats. This ejaculatory motor pattern could be registered in the urethralis muscle of the female rat after mechanical stimulation of the urethra, vagina and clitoris and consisted, as in the male rat, of a first ejaculatory motor train followed by an after-discharge component. Besides, the female genital ejaculatory motor pattern could be pharmacologically induced by the systemic injection of sodium nitroprusside with similar motor characteristics. No significant differences between the sensorial and pharmacologically induced female genital motor patterns were found. Present findings provide evidence for the presence of the genital motor pattern of ejaculation in female rats and suggest that the spinal generator for ejaculation is also present and functional in this gender.

Analysis of Variance↗

PubMed2004

Aphrodisiac properties of Montanoa tomentosa aqueous crude extract in male rats.

Cihuapatli, the Mexican zoapatle (Montanoa tomentosa) has an extensive ethnomedical history of use as a traditional remedy for reproductive impairments. During the study of the ejaculatory function in rats and by testing a set of Mexican plants with medicinal properties, we observed that crude extracts of M. tomentosa facilitated ejaculation. Thus, we decided to analyze the possibility that this plant possessed sexual stimulant properties. To that aim, copulatory behavior of sexually active male rats receiving doses of 38, 75 and 150 mg/kg of the aqueous crude extract of M. tomentosa, as it is prepared in traditional medicine, was assessed. In addition, we evaluated the effect of the 75-mg/kg dose of the extract on males with anesthetization of the genital area and on sexual behavior of sexually inactive male rats (noncopulators). Results showed that acute oral administration of crude extracts of M. tomentosa facilitates expression of sexual behavior in sexually active male rats, significantly increases mounting behavior in genitally anesthetized animals and induces the expression of sexual behavior in noncopulating males. Altogether, these data reveal a facilitatory action of this extract on sexual activity and particularly on sexual arousal. Present findings provide experimental evidence that the crude extract preparation of M. tomentosa, used as a traditional remedy, possesses aphrodisiac properties.

Animals↗

PubMed2001

Exhaustion of the coital reflex in spinal male rats is reversed by the serotonergic agonist 8-OH-DPAT.

Previous studies from our laboratory have shown that the genital motor pattern associated to the coital reflex in spinal male rats becomes exhausted when repeatedly evoked. Exhaustion of the genital motor pattern could be related to the sexual exhaustion phenomenon observed in copulating male rats. The present study was aimed to describe the features of coital reflex exhaustion and to determine if the 5-HT1A agonist 8-OH-DPAT was able to reverse exhaustion of this ejaculatory-like response. Additionally, the effect of pre-treatment with the 5-HT1A antagonist WAY 100635 on the 8-OH-DPAT induced motor response was evaluated. Results revealed that development of coital reflex exhaustion initiated with a progressive increase in the latency of response and was characterised by a change in the properties of the motor pattern itself. Once exhausted, i.v. administration of 8-OH-DPAT provoked the immediate expression of a potent motor pattern similar to the coital reflex, but in the absence of urethral stimulation. Injection of WAY 100635 induced, per se, expression of the coital reflex after exhaustion. Notwithstanding, pre-treatment with WAY 100635 was able to block the 8-OH-DPAT-induced motor response implying that its effect was exerted upon 5-HT1A receptors. Data suggest that the sexual exhaustion phenomenon might possess a spinal component.

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

PubMed2000

Sensory and motor aspects of the coital reflex in the spinal male rat.

In the present study the sensory and motor aspects of the coital reflex model in male rats were evaluated. Electromyographic reflex activity after mechanical stimulation of the urethra, penis and scrotal skin was recorded in all genital muscles. The possibility that a facilitatory mechanism of these muscular responses was located in the rat spinal cord was evaluated by removing the genital afferents. Results showed that urethral, penile and scrotal stimulation evoked the coital reflex in all genital muscles. Similarly, coital responses were obtained spontaneously in deafferentated animals. The parameters among the motor patterns evoked with the different mechanical stimuli were very similar. Parameters of spontaneous motor patterns were not importantly different from those obtained reflexively. A conspicuous difference between these responses was the presence of an after-discharge activity in genitally-stimulated animals. Additionally, it was found that this motor pattern can be exhausted with repeated stimulation. Spontaneous responses did not show the exhaustion phenomenon. Results are discussed in the context of the sensory-motor aspects of male sexual behaviour.

Animals↗

PubMedDate not supplied

Role of genital sensory information in the control of the functioning of the spinal generator for ejaculation.

An intrinsic spinal rhythm mediates fictive ejaculation (FE). In this study, the effect of genital sensory stimulation on the functioning of the spinal generator of ejaculation was investigated. To this aim, the effect of (a) stimulation of internal and external genital structures; (b) repeated elicitation of FE and (c) genital stimulation during in progress expression of FE on the rhythmic genital motor pattern of ejaculation (GMPE) was analysed in sexually experienced, spinal male rats. Results showed that the spinal intrinsic ejaculatory rhythm can be modulated by genital inputs, and that repeated stimulation modifies this rhythm, progressively inhibiting its expression. Finally, in progress GMPEs could be reset by overlapping genital stimulation, supporting the notion of the spinal cord mediating the inhibition of FE following repeated genital inflow. Results reveal the nature of the modulatory role that genital afferent information exerts on the expression of FE.

Animals↗

PubMedDate not supplied

Evidence for the presence and functioning of the spinal generator for ejaculation in the neonatal male rat.

A spinal pattern generator controls ejaculation in the male rat. In the present study, the hypothesis that the spinal generator for ejaculation was functional at early postnatal stages was evaluated. To this purpose, the expression of the ejaculatory motor pattern and its pharmacological activation in spinally transected neonatal rats from postnatal day 2 to weaning were investigated. Results revealed the presence of the rhythmic ejaculatory motor pattern in neonatal male rats. As in adult sexually experienced animals, the neonatal ejaculatory motor pattern could be elicited after the application of an ejaculation-like-releasing stimulus. The rhythmic genital motor response of neonates exhibited a gradual maturation that was reflected in its motor parameters until showing the features of the adult response at postnatal day 28. Besides, the ejaculatory motor pattern could be induced by the systemic injection of oxytocin in 7-day-old neonates as well as in adult animals. Present findings provide evidence for the presence of the spinal generator for ejaculation early during postnatal development, suggesting that its organisation is innate.

Animals↗

PubMedDate not supplied

alpha-Adrenergic agents modulate the activity of the spinal pattern generator for ejaculation.

Spinal cord transection at a thoracic level activates fictive ejaculation (FE) in the male rat. It has earlier been demonstrated that fictive motor patterns may be activated by pharmacological means and that the noradrenergic system seems to be particularly efficient in triggering locomotor fictive patterns in spinal animals. In the present study, the hypothesis was tested that the spinal noradrenergic system participates in the activation of the spinal generator for ejaculation (SGE). To this aim, the effect of the adrenergic agents, methoxamine, prazosin, clonidine, and yohimbine, upon FE was evaluated in spinal male rats using electromyographic techniques. The results obtained show that ejaculatory rhythmic patterns, accompanied by the expulsion of urethral contents and phasic penile movements, can be elicited by the intravenous (i.v.) injection of methoxamine or yohimbine. These drug-induced motor sequences appear superimposed to the intrinsic ejaculatory spinal rhythm. By contrast, i.v. injection of prazosin or clonidine blocked the expression of the spontaneous ejaculatory rhythmic pattern without inducing any other genital response. These data suggest that an increased noradrenergic tone, either by blockade of presynaptic alpha2-adrenoceptors or by stimulation of postsynaptic alpha1-adrenoceptors, results in the activation of the SGE. Present findings provide the evidence that the SGE might be importantly influenced by the noradrenergic system, which exerts a facilitatory control on the expression of the genital motor pattern of ejaculation.

Adrenergic Agents↗