RESUMO
In female rats, stimulation of the uterine cervix during mating induces two daily surges of prolactin. Inhibition of hypothalamic dopamine release and stimulation of oxytocin neurons in the paraventricular nucleus (PVN) are required for prolactin secretion. We aim to better understand how stimulation of the uterine cervix is translated into two daily prolactin surges. We hypothesize that noradrenergic neurons in the A1, A2, and locus coeruleus (LC) are responsible for conveying the peripheral stimulus to the PVN. In order to determine whether projections from these neurons to the PVN are activated by cervical stimulation (CS), we injected a retrograde tracer, Fluoro-Gold (FG), into the PVN of ovariectomized rats. Fourteen days after injection, animals were submitted to artificial CS or handling and perfused with a fixative solution. Brains were removed and sectioned from the A1, A2, and LC for c-Fos, tyrosine hydroxylase (TH), and FG triple-labeling using immunohistochemistry. CS increased the percentage of TH/FG+ double-labeled neurons expressing c-Fos in the A1 and LC. CS also increased the percentage of TH+ neurons expressing c-Fos within the A1 and A2, independent of their projections to the PVN. Our data reinforce the significant contributions of the A1 and A2 to carry sensory information during mating, and provide evidence of a functional pathway in which CS activates A1 and LC neurons projecting to the PVN, which is potentially involved in the translation of CS into two daily prolactin surges.
Assuntos
Colo do Útero/inervação , Ritmo Circadiano/fisiologia , Copulação/fisiologia , Sistema Hipotálamo-Hipofisário/fisiologia , Locus Cerúleo/fisiologia , Plexo Lombossacral/fisiologia , Bulbo/fisiologia , Vias Neurais/fisiologia , Núcleo Hipotalâmico Paraventricular/fisiologia , Animais , Transporte Axonal , Feminino , Corantes Fluorescentes , Lactotrofos/metabolismo , Locus Cerúleo/citologia , Locus Cerúleo/metabolismo , Bulbo/citologia , Bulbo/metabolismo , Proteínas do Tecido Nervoso/análise , Vias Neurais/ultraestrutura , Neurônios/química , Neurônios/metabolismo , Ovariectomia , Ocitocina/metabolismo , Prolactina/metabolismo , Proteínas Proto-Oncogênicas c-fos/análise , Ratos , Ratos Sprague-Dawley , Estilbamidinas , Tirosina 3-Mono-Oxigenase/análiseRESUMO
The ability of vaginocervical stimulation (VCS) to promote olfactory social recognition memory at different stages of the ovarian cycle was investigated in female rats. A juvenile social recognition paradigm was used and memory retention tested at 30 and 300 min after an adult was exposed to a juvenile during three 4-min trials. Results showed that an intact social recognition memory was present at 30 min in animals with or without VCS and at all stages of the estrus cycle. However, whereas no animals in any stage of the estrus cycle showed retention of the specific recognition memory at 300 min, those in the proestrus/estrus phase that received VCS 10 min before the trial started did. In vivo microdialysis studies showed that there was a significant release of oxytocin after VCS in the olfactory bulb during proestrus. There was also increased oxytocin immunoreactivity within the olfactory bulb after VCS in proestrus animals compared with diestrus ones. Furthermore, when animals received an infusion of an oxytocin antagonist directly into the olfactory bulb, or a systemic administration of alpha or beta noradrenaline-antagonists, they failed to show evidence for maintenance of a selective olfactory recognition memory at 300 min. Animals with vagus or pelvic nerve section also showed no memory retention when tested after 300 min. These results suggest that VCS releases oxytocin in the olfactory bulb to enhance the social recognition memory and that this may be due to modulatory actions on noradrenaline release. The vagus and pelvic nerves are responsible for carrying the information from the pelvic area to the CNS.
Assuntos
Memória/fisiologia , Bulbo Olfatório/metabolismo , Ocitocina/metabolismo , Reconhecimento Psicológico/fisiologia , Olfato/fisiologia , Comportamento Social , Antagonistas Adrenérgicos/farmacologia , Animais , Colo do Útero/inervação , Colo do Útero/fisiologia , Ciclo Estral/fisiologia , Feminino , Plexo Hipogástrico/anatomia & histologia , Plexo Hipogástrico/fisiologia , Imuno-Histoquímica , Neurônios Aferentes/metabolismo , Norepinefrina/metabolismo , Ocitocina/antagonistas & inibidores , Estimulação Física , Ratos , Ratos Wistar , Transmissão Sináptica/fisiologia , Vagina/inervação , Vagina/fisiologia , Nervo Vago/anatomia & histologia , Nervo Vago/fisiologia , Fibras Aferentes Viscerais/anatomia & histologia , Fibras Aferentes Viscerais/fisiologiaRESUMO
The effects of vaginocervical stimulation (VCS) on glutamate (GLU), aspartate (ASP), gamma-aminobutyric acid (GABA), noradrenaline (NA), arginine (ARG) and nitric oxide (NO) (citrulline) release in the nucleus of the solitary tract (nTS) were measured in anaesthetised female rats as a function of the oestrus cycle. During pro-oestrus/oestrus (P/E), but not during met-oestrus/di-oestrus (M/D), VCS significantly increased concentrations of NA, ASP, GLU, NO (citrulline) and GABA, but not ARG. Basal NA concentrations were also increased in P/E. These effects were prevented by bilateral section of either the vagus nerve or pelvic and hypogastric nerves. Vagotomy also significantly decreased basal NO concentrations in M/D and P/E while pelvic and hypogastric nerve section significantly increased GABA concentrations. Our results therefore confirm that the nTS is a relay structure for the visceral afferents sending information from the uterus into the central nervous system. The ability of VCS to trigger classical transmitter release and NO in the female is influenced by the stage of the oestrous cycle and is routed both via the vagus and pelvic/hypogastric nerves.
Assuntos
Estro/fisiologia , Genitália Feminina/inervação , Neurônios/metabolismo , Neurotransmissores/metabolismo , Óxido Nítrico/metabolismo , Núcleo Solitário/metabolismo , Fibras Aferentes Viscerais/fisiologia , Animais , Arginina/metabolismo , Ácido Aspártico/metabolismo , Colo do Útero/inervação , Colo do Útero/fisiologia , Denervação/efeitos adversos , Feminino , Genitália Feminina/fisiologia , Ácido Glutâmico/metabolismo , Plexo Hipogástrico/fisiologia , Plexo Hipogástrico/cirurgia , Microdiálise , Neurônios/citologia , Norepinefrina/metabolismo , Estimulação Física , Ratos , Ratos Wistar , Núcleo Solitário/citologia , Vagina/inervação , Vagina/fisiologia , Nervo Vago/fisiologia , Nervo Vago/cirurgia , Fibras Aferentes Viscerais/citologia , Ácido gama-Aminobutírico/metabolismoRESUMO
In anesthetized rats it was tested whether or not the activity of the ON and OFF cells within the rostral ventromedial medulla (RVM) is modulated by the mechanical stimulation of the uterine cervix (VS). ON cells were identified by an abrupt increase in their firing rate before the tail flick in response to a noxious heat. OFF cells were identified by a sudden decrease in their firing rate before the tail flick. All (27 out of 27) identified ON cells decreased their firing rate immediately after VS was applied. The effect of VS on the activity of the cells persisted for the entire stimulation period. On the other hand, all (19 out of 19) identified OFF cells increased their firing rate immediately after VS. The effect of VS on the activity of these cells also persisted for the entire stimulation period. The activity of the neutral cells showed no change, neither during the application of noxious heat, nor during VS. These results suggest that the analgesic-like effect produced by VS can be mediated by the activity of the antinociceptive circuit at the RVM. Alternatively, it can be suggested that the afferent inflow from the genital tract can induce the activity of the antinociceptive circuit at RVM, either by projections to the periaqueductal gray matter or by direct projections to RVM.
Assuntos
Colo do Útero/inervação , Bulbo/fisiologia , Dor/fisiopatologia , Vagina/inervação , Animais , Potenciais Evocados/fisiologia , Feminino , Temperatura Alta , Bulbo/citologia , Ratos , Ratos Wistar , Estresse MecânicoRESUMO
The rise in blood pressure and heart rate produced by the mechanical stimulation of the uterine cervix (VS) was examined after adrenalectomy, after pelvic or hypogastric neurectomies or after spinal cord transection in anesthetized rats. Neither adrenalectomy, nor hypogastric neurectomy prevented the rise in heart rate and blood pressure produced by VS. After the spinal cord transection at T6 level, VS was still able to produce the rise in blood pressure. However, the rise in blood pressure was significantly lower than that produced in the same animals before the transection. No changes in heart rate were produced by VS after spinal cord transection. This result can be explained because this level of transection prevents the reach of the afferent inflow to the superior cervical ganglia. Pelvic neurectomy abolished completely the effects of VS on blood pressure and heart rate. Low intensity (1-2 times the threshold) electrical stimulation of the pelvic nerve produced a rise in blood pressure. Even though heart rate increased during electrical stimulation, the change in heart rate was not statistically different from the pre-stimulation value. These results suggest that the changes in blood pressure and heart rate produced by VS represent a neuronal reflex response mediated by the pelvic nerve. The fact that the effects of VS on blood pressure persist in spinal cord-transected animals suggests that the reflex is integrated at the spinal level. However, the cardiovascular responses to VS were significantly lower than before transection, suggesting that supraspinal centers are also involved in the reflex.
Assuntos
Pressão Sanguínea/fisiologia , Colo do Útero/inervação , Frequência Cardíaca/fisiologia , Sistema Nervoso Simpático/fisiologia , Vagina/inervação , Adrenalectomia , Anestesia , Animais , Denervação Autônoma , Fenômenos Fisiológicos Cardiovasculares , Sistema Cardiovascular/inervação , Colo do Útero/irrigação sanguínea , Colo do Útero/fisiologia , Estimulação Elétrica , Feminino , Plexo Hipogástrico/cirurgia , Pelve/inervação , Ratos , Ratos Wistar , Medula Espinal/cirurgia , Vagina/irrigação sanguínea , Vagina/fisiologiaRESUMO
The plasticity of the sympathetic and sensory innervation of the rat uterus was examined, before and after puberty, in controls and in animals where primary sensory nerves had been destroyed by neonatal capsaicin treatment. Immunohistochemical and histochemical methods were used in association with nerve density measurements and biochemical assays. The main findings were as follows: (1) Puberty was associated with a marked increase in the weight of the uterine horn, uterine cervix and parametrial tissue. This was unaffected by capsaicin treatment. (2) The sympathetic innervation of the uterine horn and parametrial tissue was reduced following puberty as revealed by a decrease in the density of noradrenaline-containing nerves and a marked decrease in the tissue concentration of noradrenaline. Sympathetic nerves supplying the uterine cervix and the blood vessels of the uterus appeared to be unaffected by puberty. (3) In contrast, the sensory supply of the uterus by substance P and calcitonin gene-related peptide-containing nerves increased in parallel with uterine growth during puberty resulting in no change in nerve density and only a slight reduction in peptide concentration. (4) Neonatal capsaicin treatment caused a long-lasting depletion of substance P- and calcitonin gene-related peptide-containing nerves. In the uterine horn and parametrial tissue, capsaicin-resistant calcitonin gene-related peptide, but not substance P, still increased with tissue weight during puberty, indeed, in the uterine horn, the relative increase was greater than in controls. (5) Sensory denervation resulted in an increase in the non-vascular sympathetic supply of the uterus, although there was a regional variation in the time course of the response. Perivascular sympathetic nerves were unaffected by capsaicin treatment. The pattern of change in non-vascular noradrenaline-containing nerves associated with puberty was similar in nature to controls. Thus, there is considerable plasticity in the innervation of the uterus both during puberty and following sensory denervation. A complex pattern of change occurs with differential responses in vascular and nonvascular nerves and in different regions of the uterus. Such differences may be due in part to the different origins of individual nerve populations and/or to their relative sensitivities to sex hormones.
Assuntos
Capsaicina/toxicidade , Neurônios Aferentes/efeitos dos fármacos , Sistema Nervoso Simpático/efeitos dos fármacos , Útero/inervação , Animais , Animais Recém-Nascidos , Vasos Sanguíneos/inervação , Peso Corporal/efeitos dos fármacos , Peptídeo Relacionado com Gene de Calcitonina/análise , Colo do Útero/crescimento & desenvolvimento , Colo do Útero/inervação , Feminino , Fibras Nervosas/efeitos dos fármacos , Plasticidade Neuronal , Norepinefrina/análise , Ratos , Ratos Wistar , Maturidade Sexual , Substância P/análise , Simpatectomia Química , Útero/irrigação sanguínea , Útero/crescimento & desenvolvimentoRESUMO
In decerebrate or spinal cats, sustained mechanical stimulation of the cervix uteri inhibited the flexor reflex elicited by electrical stimulation of the foot pad during the probing period (160 s). After probing, 3-15 min were required for reflex recovery. No additional inhibition was produced if probing was repeated before recovery, but instead the reflex was facilitated. When probing was applied 5-10 min after reflex recovery the reflex was again abolished. The recovery, however, occurred earlier and was followed by facilitation. Probing the cervix with single mechanical pulses inhibited transiently (140-200 ms) the short latency reflex components, but the components with longer latencies are unaffected or facilitated. Distension of the vaginal wall with a balloon also inhibited the flexor reflex, but a transient, mild facilitation appeared several seconds after the distension. In general, whenever the inhibition decreases, the facilitation predominates. Our findings suggest that cervical probing or vaginal distension triggers both a long-lasting inhibition and a concomitant facilitation in different intraspinal flexor reflex pathways.
Assuntos
Colo do Útero/fisiologia , Reflexo , Sinapses/fisiologia , Vias Aferentes/fisiologia , Animais , Gatos , Colo do Útero/inervação , Estado de Descerebração , Feminino , Músculo Liso/inervação , Músculo Liso/fisiologia , Estimulação Física , Medula Espinal/fisiologia , Fatores de Tempo , Vagina/fisiologiaRESUMO
In decerebrate cats, controlled mechanical stimulation of the perivulvar skin, the vaginal wall or the cervix uteri induced visible hind limb extension. Pressing on the cervix uteri produced the greater response. To quantify these responses, the EMG activity and the tension developed by the normally inserted triceps surae muscles were recorded. The activity induced in these muscles by stimulation of the genital canal outlasted the stimulus by many seconds or a few minutes. These effects disappeared after spinalization at the T12 level. We propose that stimulation of the vaginal canal in the female cat may induce bistability of triceps surae motoneurones.
Assuntos
Colo do Útero/fisiologia , Músculos/fisiologia , Fenômenos Fisiológicos da Pele , Vagina/fisiologia , Vulva/fisiologia , Animais , Gatos , Colo do Útero/inervação , Copulação/fisiologia , Estado de Descerebração , Eletromiografia/instrumentação , Eletromiografia/métodos , Potenciais Evocados , Feminino , Músculo Liso/inervação , Músculo Liso/fisiologia , Estimulação Física , Pele/inervação , Vagina/inervação , Vulva/inervaçãoRESUMO
Mitral cell layer neuronal activity in the olfactory bulb (OB) of the anesthetized rat is modulated by cervicovaginal distension. Data are reported on 22 cells that decreased and 6 that increased in response to the distension. These results provide support for the existence of a functional interaction between the reproductive tract and the olfactory system.