Cytoarchitectural impairments in the medium spiny neurons of the Nucleus Accumbens core of hyperactive juvenile rats.

Dopaminergic activity in the Nucleus Accumbens has been strongly implicated in the motor hyperactivity associated with Attention deficit hyperactivity disorder. Dopaminergic and glutamatergic terminals converge on the dendritic spines of medium spiny neurons of the nucleus accumbens core, which modulate the excitatory glutamatergic activity. In this work, a Golgi study was carried out to investigate the effects of dopamine depletion on the cytoarchitecture of dendritic spines of nucleus accumbens core medium spiny neurons. The dopaminergic system of newborn male rats was lesioned intracisternally by using 6-hydroxydopamine, and subsequently, the motor activity, spine density, and the proportion of thin, stubby, mushroom, wide, branched, and double spines was compared to those in control and intact animals. Motor activity was significantly increased in the dopamine-depleted animals and while the spine density was reduced, there was no change in the proportion of the specific types of spines. Larger thin spines were observed in the dopamine-depleted animals. Indeed, dopamine depletion may lead to spine retraction due to the disregulation of spine development, and/or an increase in glutamatergic activity. The enlargement of thin spines may suggest a compensatory mechanism to increase the efficiency of synaptic inputs in response to a decrease in spines number. Together, the present findings suggest an alteration to the excitatory/inhibitory balance on dendritic spines of medium spiny neurons of the nucleus accumbens core in hyperactive juvenile rats following early dopamine depletion.

Presentación clínica de coartación de aorta, relato de casos: revisión de manejo actual / Clinical presentation of aortic coarctation: review of current management: a case series report

La coartación de Aorta es una cardiopatía congénita que se presenta con insuficiencia cardiaca congestiva precozmente sobre todo en la edad neonatal y que, de no ser diagnosticada oportunamente evoluciona con elevadísima morbi-mortalidad. Cuando sobrevive a la barrera de la primera infancia, cursa con hipertensión arterial sistémica, pudiendo debutar incluso con un accidente cerebrovascular, con resultado fatal para el paciente, ó dejarlo con incapacidades como secuela. Resaltamos la importancia del correcto y detallado examen clínico cardiovascular, que incluya la palpación adecuada de los pulsos periféricos así como la medición de la presión arterial sistémica, debido a que siempre cursa con hipertensión arterial en los miembros superiores y ausencia de pulsos en los miembros inferiores. Tratado correctamente presenta bajo riesgo de complicaciones y de mortalidad.

Aortic coarctation is a congenital heart defect that presents with early congestive heart failure, especially during the neonatal stage, and which if not opportunely diagnosed progresses with a high degree of morbidity and mortality. When patients survive the barrier of early childhood, they continue having such problems as systemic arterial hypertension, and run risks of outcomes such as fatal or incapacitating cerebrovascular accident. We emphasize the importance of a careful and detailed clinical cardiovascular examination, to include adequate taking of the peripheral pulses and measurement of systemic blood pressure, since this always presents with hypertension in the upper limbs and an absence of pulses in the legs. Treated adequately, it presents little risk of complications or mortality.

Es la prueba del lazo un buen predictor de complicaciones hemorrágicas en pacientes con dengue? / Is the test of the tie a good predictor of hemorragic complication in patients with dengue?

Introducción: El dengue es una enfermedad que puede cursar con complicaciones hemorragicas. La prueba del lazo es un método recomendado como criterio diagnóstico de Fiebre Hemorrágica Dengue. Objetivos: Describir las manifestaciones hemorrágicas más frecuentes, hallar la sensibilidad y especificidad de la prueba del lazo, en relación al recuento de plaquetas y a la presencia de manifestaciones hemorrágicas espontáneas. Metodología: diseño observacional descriptivo, retrospectivo, de corte transverso, con componentes analíticos. Población de estudio: se estudiaron 245 pacientes, 170 mujeres (69%) y 75 varones (31%), con cuadro clínico compatible con dengue, que consultaron entre diciembre 2006 abril 2007 en el Hospital Nacional. Muestreo: no probabilístico, de casos consecutivos. Resultados:Las manifestaciones hemorrágicas espontáneas más frecuentes fueron las petequias 18 casos (7,3 %) , gingivorrágias 14 casos (5,7%) y epistaxis 11 casos (4,5 %) La sensibilidad y especificidad de la prueba del lazo, en relación con el recuento de plaquetas , fue del 27,7% y 84,5%. La prueba del lazo, en relación a la presencia de manifestaciones hemorrágicas, presentó una sensibilidad del 30,7% y especificidad del 85,4%. Conclusiones: La prueba del lazo no fue un buen método predictor de aparición de manifestaciones hemorrágicas por su baja sensibilidad. Sin embargo, cunado está ausente, ungran porcentaje de los pacientes no presentaron manifestaciones hemorrágicas, lo que dió una alta espeficidad...

[Clinical nutrition knowledge in health care members of University Hospitals of Paraguay]. / Nivel de conocimiento en nutrición clínica en miembros del Equipo de Salud de Hospitales Universitarios del Paraguay.

BACKGROUND: Adequate clinical nutrition care is an integral part of the complete treatment of hospitalised patients, requiring specific knowledge from the health care team. The aim of this study is to assess, in Paraguay, the health care team ability in clinical care nutrition. MATERIALS AND METHODS: A survey was made including 174 people of Paraguay university hospitals (29% physicians, 29% medicine graduating students, 11% pharmaceutics, 24% nurses, 7% dieticians), by answering voluntarily a multiple choice questionnaire of 20 items. RESULTS: The median score of the 20 questions was 6 (0-15). Physicians obtained a median of 6 (2-15), graduating students 7 (2-14), pharmaceutics 7 (0-15), nurses 3 (0-11), and dieticians 9 (4-13). The dieticians obtained a significantly higher score than the other groups (p < 0.005). CONCLUSIONS: The knowledge about clinical nutrition in the health care members from university hospitals is not adequate. The level of education in clinical nutrition is better in the dietician.

Nivel de conocimiento en nutrición clínica en miembros del Equipo de Salud de Hospitales Universitarios del Paraguay / Clinical nutrition knowledge in health care members of university hospitals of Paraguay

Introducción: Cuidados adecuados de nutrición clínica constituyen parte integral del completo tratamiento de los pacientes hospitalizados. Para la práctica correcta de la terapia nutricional, los profesionales del equipo de salud necesitan conocimientos específicos. Es de interés conocer el nivel de estos conocimientos en el Paraguay. Materiales y métodos: A 174 personas de hospitales universitarios del Paraguay (29% médicos, 29% estudiantes de sexto año de Medicina de la Universidad Nacional de Asunción, 11% farmacéuticos, 24% licenciados en enfermería, 7% nutricionistas) se suministró un cuestionario de selección múltiple de 20 puntos para determinar el nivel de conocimiento en nutrición según la calificación obtenida. Resultados: La calificación mediana de un total de 20 puntos fue de 6 (0-15). Los médicos obtuvieron una mediana de 6 (2-15), los estudiantes 7 (2-14), los farmacéuticos 7 (0-15), los licenciados en enfermería 3 (0-11) y las nutricionistas 9 (4-13). El puntaje de las nutricionistas fue significativamente mayor que el de los otros grupos (p < 0,005). Conclusión: La formación en nutrición clínica en el personal de blanco de hospitales universitarios en Paraguay no es completa. El nivel de conocimiento es superior en las nutricionistas (AU)

Background: Adequate clinical nutrition care is an integral part of the complete treatment of hospitalised patients, requiring specific knowledge from the health care team. The aim of this study is to assess, in Paraguay, the health care team ability in clinical care nutrition. Materials and methods: A survey was made including 174 people of Paraguay university hospitals (29% physicians, 29%medicine graduating students, 11% pharmaceutics, 24% nurses, 7% dieticians), by answering voluntarilya multiple choice questionnaire of 20 items. Results: The median score of the 20 questions was 6 (0-15). Physicians obtained a median of 6 (2-15), graduating students 7 (2-14), pharmaceutics 7 (0-15), nurses 3 (0-11), and dieticians 9 (4-13). The dieticians obtained a significantly higher score than the other groups (p <0.005). Conclusions: The knowledge about clinical nutrition in the health care members from university hospitals is not adequate. The level of education in clinical nutrition is better in the dietician (AU)

Cholinergic facilitation of erection and ejaculation in spinal cord-transected rats.

Penile reflexes (PRs) were monitored in chronic spinal cord-transected rats by identifying them visually, and at the same time they were recorded as the electromyographic activity of bulbospongiosus muscles. Intraperitoneal injection of the agonist muscarine (10 microg) produced a facilitation of PRs. A decrease in the latency, an increase in the number of clusters and often an increase in the duration of cups were found after muscarine. In addition, 66% (six out of nine) of the animals ejaculated after muscarine. These results suggest that cholinergic receptor stimulation may be involved in erectile and ejaculatory mechanisms mediated by the spinal cord.

Muscarinic mediation of the urethro genital reflex in spinal cord-transected rats.

The effects of muscarinic receptor stimulation were tested on the urethro genital reflex (UGR) in anesthetized and spinal cord-transected rats. Drugs were applied directly to the spinal cord. The electromyographic activity (EMG) of the bulbospongiosus (BS) muscle was used for recording UGR. In six animals BS as well as soleus, posterior biceps or peroneus tertius muscle EMG was recorded simultaneously. Muscarine (5, 10, 20, 50 and 100 microg) was applied in 22 animals after cutting L6-S1 dorsal roots. Some observations were made on another six animals, to which an extensive bilateral dorsal rhizotomy (L3-S2) was performed. Rhythmic bursts of similar frequency and size to those seen during UGR were found in BS muscle a few minutes after muscarine application. No rhythmic bursting was found on the hindlimb muscles, but exclusively on BS muscles. The effects of homatropine (25, 50, 100 and 200 microg), an acetylcholine muscarinic receptor antagonist, were tested in 21 rats after UGR was elicited three times at low stimulation intensity (7 mm Hg). Homatropine produced two effects: (i) A significant increase in the latency of UGR. (ii) A facilitation of UGR inhibition. In view of these results it can be speculated that muscarinic receptor stimulation is involved in the elicitation of UGR.

Masculine copulatory behavior is facilitated by intrathecally administered muscarine.

Behavioral experiments were conducted to examine the role of the cholinergic receptor-agonist muscarine or its antagonist homatropine on the mating behavior of sexually experienced male rats. Male copulatory behavior was recorded after intrathecally administered saline, muscarine (7.5 microg), or homatropine (25 microg). Changes in copulatory behavior were assessed by the following parameters: intromission latency, intromission frequency, intercopulatory interval, ejaculation latency, and postejaculatory interval. Intromission frequency, intercopulatory interval, and ejaculation latency were decreased significantly by muscarine. Intrathecal homatropine decreased the number of copulating animals (five out of 13). In the five animals that were able to ejaculate after homatropine, intromission latency, intercopulatory interval, and ejaculation latency increased significantly. The effects of both drugs on locomotion were also tested. Muscarine induced no significant changes in locomotion compared with saline. A significant increase in locomotion was found after homatropine treatment. These results suggest that acetylcholine, acting at spinal-cord muscarinic receptors, may be involved in ejaculation.

La actividad de las células excitadoras e inhibidoras de la médula rostroventromedial está modulada por la estimulación vaginocervical / The acti vity of ON and OFF cells at the rostro ventromedial medulla is modulated by vagino-cervical stimulation

En ratas anestesiadas se estudió si la actividad de las células excitadoras e inhibidoras de la médula ro s t ro v e n t romedial estaba modulada por la estimulación mecánica del cuello uterino. Las células excitadoras se identificaron por un brusco aumento de la frecuencia de impulsos antes de p roducirse el movimiento de la cola en respuesta a un estímulo térmico doloroso. Las células inhibidoras se identificaron por un súbito descenso de la frecuencia de impulsos justo antes de producirse el movimiento de la cola. Todas las células excitadoras identificadas (27 de 27) re d u j e ron su f recuencia de impulsos inmediatamente después de la aplicación de un estímulo vaginal. El efecto del estímulo vaginal en la actividad de las células persistió durante todo el periodo de estimulación. Por otra parte, todas las células inhibidoras identificadas (19 de 19) aumentaron su frecuencia de impulsos después del estímulo vaginal. El efecto del estímulo vaginal en la actividad de estas células persistiótambién durante todo el periodo de estimulación. La actividad de las células neutrales no mostró cambio alguno, ni durante la aplicación de un estímulo térmico doloroso ni durante el estímulo vaginal. Estos resultados sugieren que el efecto analgésico producido por el estímulo vaginal puede estar mediado por la actividad del circuito antinociceptivo en la médula rostroventromedial. Además, se ha sugerido que el influjo aferente del tracto genital puede inducir la actividad del circuito antinociceptivo en la médula rostroventromedial, ya sea mediante proyecciones a la sustancia gris periacueductal o proyecciones directas a la médula rostroventromedial (AU)

The activity of ON and OFF cells at the rostroventromedial medulla is modulated by vagino-cervical stimulation.

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.

Cardiovascular responses to vaginocervical stimulation in the spinal cord-transected rat.

The present study ascertained whether increases in heart rate (HR) and systolic blood pressure (SBP) produced by vaginocervical stimulation (VS; 500 g force) persist in the unanesthetized rat after chronic spinal cord transection at selected levels. Three groups were used: spinal cord transection at T7 (n = 10) or L5 (n = 10) or a sham-operated control group (Sh, n = 10). In the Sh group, VS increased significantly both HR, by 95 +/- 14.3 beats/min (bpm) (22 +/- 3.7% above baseline), and BP, by 37 +/- 5.7 mmHg (37 +/- 7.7% above baseline), confirming earlier findings. In the T7 group, VS significantly decreased HR by 107 +/- 21.4 bpm (27 +/- 4.1% below baseline) and increased BP by 41.3 +/- 12.9 mmHg (32 +/- 8.3% above baseline). In response to VS, HR increased in every rat in the Sh group and decreased in every rat in the T7 group. In the L5 group, VS failed to significantly affect HR or BP. In the present study, specific levels of spinal cord transection produced differential HR and BP responses to VS in the rat. A model is presented addressing the component responses of autonomic dysreflexia that can occur, contingent on the level of spinal cord injury, in women during parturition or sexual intercourse.

Facilitation and inhibition of the urethrogenital reflex in spinal cord-transected rats.

It was evaluated in the spinal cord-transected rats whether the urethrogenital (UG) reflex shows some of the features that are present during ejaculation in intact animals. It was found that the UG reflex was facilitated after its first elicitation: the latency of the reflex was shorter than the previous one and low intensity of stimulation was needed to produce the reflex. In addition, a change in the latency of the reflex was found that was correlated with the number of stimulation trials. The latency change showed a J-shaped curve that is similar to that found for the ejaculation latency in a copulatory series. An inhibition of the reflex appeared after several trials: the reflex could not be elicited after three continuous trials. The reflex could be elicited again if the intensity of stimulation was increased. The UG reflex also showed 'exhaustion': it could not be elicited, even with high intensities of stimulation, after 3 h of rest. All these findings were present when the UG reflex was elicited by applying pressure to the urethra or when it was evoked by the electrical stimulation to the pudendal nerve. According to these findings, it can be concluded that the UG reflex maintains some of the features that are found during ejaculation in intact animals. According to this view, it can be speculated that some of the mechanisms that control ejaculation in intact animals can be localized at a spinal level.

Neural mechanisms accounting for the increase in blood pressure and heart rate during vagino-cervical stimulation.

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.

Vagotomy blocks responses to vaginocervical stimulation after genitospinal neurectomy in rats.

To ascertain whether any effects of vaginocervical stimulation (VS) are mediated by the vagus nerve, all known afferent nerves from the reproductive tract to the spinal cord were transected and the rats were tested for residual responses to VS. After combined bilateral transection of the pelvic, hypogastric, and pudendal nerves (NX), the following responses to VS were greatly reduced or abolished: lordosis to flank-perineum palpation, leg extension, immobilization, and blockage of both tail withdrawal to radiant heat and leg withdrawal to foot pinch. However, after these nerve cuts, the following persisted as significant residual responses to VS: 1) analgesia [measured as increase in vocalization threshold (VOCT) to tailshock], 2) pupil dilatation (PD), and 3) increase in heart rate (HR). Subsequent bilateral subdiaphragmatic vagotomy (VX) significantly reduced the magnitude of PD and abolished the analgesia. By contrast, VX produced no significant effect on the HR increase to VS. The above findings provide evidence that brain-mediated responses to vaginocervical stimulation can be elicited via the vagus nerves.

Brain-mediated responses to vaginocervical stimulation in spinal cord-transected rats: role of the vagus nerves.

The present study was designed to ascertain whether the vagus nerves convey functional sensory activity from the reproductive tract in rats. Previously, vaginocervical mechanostimulation (VS) was shown to increase pupil diameter (PD) and the threshold of vocalization to tail shock (Voc-T). These responses were attenuated but not abolished by combined bilateral transection of the 'genito-spinal' nerves (i.e. pelvic, hypogastric and pudendal). Subsequent bilateral vagotomy further reduced or abolished the residual responses. In the present study, spinal cord transection above the known level of entry of the genito-spinal nerves was combined with bilateral vagotomy. In ovariectomized rats, after spinal cord transection at thoracic 7 (T7X), lumbar 5 (L5X) levels, or sham surgery (Sh), responses to VS were measured, the vagus nerves were then transected bilaterally, and responses to VS were again measured. VS significantly increased Voc-T and PD after sham procedure or spinal cord transection at either level. Subsequent bilateral vagotomy abolished the VS-induced increase in PD in the T7X group. Due to low survival rate, the effect of vagotomy on Voc-T could not be determined. Consequently, we performed a second experiment. In non-ovariectomized rats, VS significantly increased PD but reduced Voc-T in the T7X group compared to the Sh group, and subsequent bilateral vagotomy abolished both responses. These findings provide evidence that, in the rat, the vagus nerves provide a functional sensory pathway from the reproductive tract directly to the medulla oblongata of the brain, bypassing the spinal cord.

Inhibition of withdrawal responses by pelvic nerve electrical stimulation.

In urethane-anesthetized rats, the compound action potential of the pelvic nerve was found to consist of three different waves, two in the A delta fiber and one in the C-fiber range of conduction velocity. Electrical stimulation of the pelvic nerve produced a complete inhibition of the withdrawal response to noxious foot pinch or foot compression. The electromyographic (EMG) activity of the contralateral posterior biceps muscle was used to record the withdrawal response. The withdrawal response inhibition was related to the duration and the frequency of electrical stimulation. Low (5-10 Hz) and high (100-300 Hz) frequencies were ineffective in inhibiting the withdrawal response, whereas intermediate frequencies (20-80 Hz) produced a complete inhibition of the withdrawal response. Short (300 ms) trains of stimulation inhibited the withdrawal response only during the stimulation period. Longer trains of stimulation (500 ms-10 s) produced long-lasting inhibition of the response to noxious stimulation. The inhibition persisted for up to 20 s after the end of electrical stimulation of the pelvic nerve. A delta fiber stimulation was adequate to inhibit the withdrawal response in most (15 out of 17) of the animals. However, A delta plus C-fiber stimulation was needed to inhibit the response to noxious stimulation in two animals. In addition to inhibiting the response to noxious stimulation, pelvic nerve electrical stimulation reflexively activated abdominal muscles. On the basis of present findings using electrical stimulation, it can be suggested that, in the rat, A delta and C-visceral afferents of the pelvic nerve mediate the analgesic effect of vaginocervical probing pelvic and A delta afferents the contraction of abdominal muscles in the fetus-expulsion reflex.

Disposition kinetics of HEPP in rats after intravenous, oral, and intraperitoneal administration. Correlation of plasma and brain levels with the anticonvulsant effect.

D, L-3-hydroxy-3-ethyl-3-phenylpropanamide (HEPP) is a synthetic drug with anticonvulsant effects in a variety of seizure models. HEPP pharmacokinetics was studied after single 50 mg kg-1 intravenous (i.v.), intraperitoneal (i.p.), and oral (PO) administration in male albino Wistar rats. The plasma concentration against time curves showed a biphasic decay pattern with a similar distribution phase and the same terminal rate constant (beta = 0.22 h-1) by all three routes. The apparent volume of distribution at steady state (Vss = 0.80 L kg-1) indicates that HEPP is extensively distributed in extracellular tissues. This finding agrees very well with its low binding to plasma protein (mean bound fraction = 19.3 +/- 1.1%). The systemic clearance (Cl) was very low (3.30 mL min-1 kg-1). The bioavailability after IP and PO administration was 0.80 and 0.60 respectively. In the pharmacokinetic-pharmacodynamic studies a direct relationship was found between the protective effect of HEPP against pentylenetetrazole (PTZ) induced seizures and its concentration in plasma and/or brain. The concentrations at half-maximal effect (EC50) with 95% confidence interval (Cl) were 70.6 (66-75.5) micrograms mL-1 in serum and 60.1 (55.4-65.1) micrograms g-1 in brain. There was a rapid uptake of HEPP into the brain, and after the distributive phase, the disappearances in plasma and brain were almost parallel [C(serum) = 109 e-0.25t, r2 = 0.95; C(brain) = 38 e-2.53t + 91 e-0.21t, r2 = 0.93], with a C(brain)/C(plasma) ratio of 1.1.

The cat pudendal nerve: afferent fibers responding to mechanical stimulation of the perineal skin, the vagina or the uterine cervix.

Some afferent fibers from the pudendal nerve of the female cat were stimulated by pressing on the perineal skin, the vagina or the uterine cervix. Three different types of skin mechanoreceptors were found: (1) with low threshold (< 20 mg) and slow-adapting discharges; (2) with high threshold (0.1-0.5 g) and slow-adapting discharges; and (3) with low threshold and fast-adapting discharges. Most of these receptors increased their firing frequency as the velocity of skin indentation was increased (velocity detectors). The average conduction velocity of the skin afferents was 29 +/- 9 m/s. The receptors located at the vagina showed a fast-adapting response to probing and were sensitive to the velocity of the probe movement. Most of these receptors, however, showed a slow adaptation when the vaginal wall was distended with a balloon. The conduction velocity in vaginal afferents was 37 +/- 16 m/s. Those receptors responding to pressure on the uterine cervix adapted slowly to constant pressure but were sensitive to the velocity of the pressure pulses. The conduction velocity in the afferents from the uterine cervix was 31 +/- 9 m/s.

Prolonged inhibition of the flexor reflex by probing the cervix uteri in the cat.

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.

Sustained activation of the triceps surae muscles produced by mechanical stimulation of the genital tract of the female cat.

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.