The influence of menstrual phase on synaptic plasticity induced via intermittent theta-burst stimulation.

BACKGROUND: Ovarian hormones influence the propensity for short-term plasticity induced by repetitive transcranial magnetic stimulation (rTMS). Estradiol appears to enhance the propensity for neural plasticity. It is currently unknown how progesterone influences short-term plasticity induced by rTMS. OBJECTIVE: The present research investigates whether the luteal versus follicular phase of the menstrual cycle influence short-term plasticity induced by intermittent theta-burst stimulation (iTBS). We tested the hypothesis that iTBS would increase motor evoked potentials (MEPs) during the follicular phase. Further, we explored the effects of the luteal phase on iTBS-induced neural plasticity. METHOD: Twenty-nine adult females participated in a placebo-controlled study that delivered real and sham iTBS to the left primary motor cortex in separate sessions corresponding to the follicular phase (real iTBS), luteal phase (real iTBS), and a randomly selected day (sham iTBS). Outcomes included corticospinal excitability as measured by the amplitude of MEPs and short-interval intracortical inhibition (SICI) recorded from the right first dorsal interosseous muscle before and following iTBS (612 pulses). RESULTS: MEP amplitude was increased following real iTBS during the follicular condition. No significant changes in MEP amplitude were observed during the luteal or sham visits. SICI was unchanged by iTBS irrespective of menstrual phase. CONCLUSION: These findings suggest women experience a variable propensity for iTBS-induced short-term plasticity across the menstrual cycle. This information is important for designing studies aiming to induce plasticity via rTMS in women.

Role of cholinergic and adrenergic pathways of the medial septal area in the control of water intake and renal excretion in rats.

In this study, we investigated an interaction between noradrenergic and cholinergic pathways of the medial septal area (MSA) on the control of water intake and urinary electrolyte excretion by means of injection of their respective agonists. Noradrenaline (a nonspecific alpha-adrenergic agonist) and clonidine (an alpha 2-adrenergic agonist), but not phenylephrine (an alpha 1-adrenergic agonist), induced natriuresis and kaliuresis. alpha-Adrenergic activation had no effect on the natriuresis and kaliuresis induced by carbachol (a cholinergic agonist) and it inhibited the antinatriuresis and antikaliuresis induced by isoproterenol (a beta-adrenergic agonist). Interactions related to volume excretion are complex, alpha-Adrenergic activation induced a mild diuresis and inhibited the antidiuresis induced by isoproterenol, but phenylephrine combined with carbachol induced antidiuresis. The water intake induced by carbachol was inhibited by clonidine and noradrenaline, but not phenylephrine. These results show an asymmetry in the interaction between alpha-adrenergic and cholinergic receptors concerning water intake and electrolyte excretion.

Functional evidence that the central renin-angiotensin system plays a role in the pressor response induced by central injection of carbachol.

We investigated the effects of losartan, an AT1-receptor blocker, and ramipril, a converting enzyme inhibitor, on the pressor response induced by angiotensin II (ANG II) and carbachol (a cholinergic receptor agonist). Male Holtzman rats (250-300 g) with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The injection of losartan (50 nmol/1 microliter) into the LV blocked the pressor response induced by ANG II (12 ng/1 microliter) and carbachol (2 nmol/1 microliter). After injection of ANG II and carbachol into the LV, mean arterial pressure (MAP) increased to 31 +/- 1 and 28 +/- 2 mmHg, respectively. Previous injection of losartan abolished the increase in MAP induced by ANG II and carbachol into the LV (2 +/- 1 and 5 +/- 2 mmHg, respectively). The injection of ramipril (12 ng/1 microliter) prior to carbachol blocked the pressor effect of carbachol to 7 +/- 3 mmHg. These results suggest an interaction between central cholinergic pathways and the angiotensinergic system in the regulation of arterial blood pressure.

Congenital constriction band of the upper arm: the role of three-dimensional ultrasound in diagnosis, counseling and multidisciplinary consultation.

Constriction band syndrome represents a sporadic condition that may result in amputations, constrictions and other deformities of the fetal limbs and body. Prenatal diagnosis by two-dimensional ultrasound has been reported. We present a case of constriction band involving the upper arm in which the assessment by three-dimensional ultrasound significantly contributed to the diagnosis and the multidisciplinary counseling. In fact, multiplanar imaging and surface rendering allowed a clear depiction of the extent of the constriction, the club-hand deformity and the relationship between the amniotic band, the cord and the fetal limb. This case represents a unique and effective application of three-dimensional ultrasound in prenatal diagnosis.

Pena-Shokeir phenotype with variable onset in three consecutive pregnancies.

The Pena-Shokeir phenotype represents an autosomal recessive syndrome characterized by neurogenic arthrogryposis, facial anomalies and pulmonary hypoplasia. Prenatal diagnosis of this disease has been reported prospectively and in cases with positive family history. We describe here a patient who has had three consecutive pregnancies affected by the Pena-Shokeir syndrome. In these pregnancies, the onset of the arthrogryposis varied between the 12th and the 18th week of gestation. Therefore, the possibility of a variable chronological development of the main diagnostic feature of the syndrome, arthrogryposis, has to be taken into proper consideration while counseling families with a positive history for the Pena-Shokeir phenotype.

Functional evidence that the central renin-angiotensin system plays a role in the pressor response induced by central injection of cabachol

We investigated the effects of losartan, an AT1-receptor blocker, and ramipril, a converting enzyme inhibitor, on the pressor response induced by angiotensin II (ANG II) and carbachol (a cholinergic receptor agonist). Male Holtzman rats (250-300 g) with a stainless steel cannula implanted into the lateral ventricle (LV) were used. The injection of losartan (50 nmol/l mul) into the LV blocked the pressor response induced by ANG II (12 ng/1 mul) and carbachol (2 nmol/ 1 mul). After injection of ANG II and carbachol into the LV, mean arterial pressure (MAP) increased to 31 + 1 and 28 + 2 mmHg, respectively. Previous injection of losartan abolished the increase in MAP induced by ANG II and carbachol into the LV (2 + 1 and 5 + 2 mmHg, respectively). The injection of ramipril (12 ng/ 1 mul) prior to carbachol blocked the pressor effect of carbachol to 7 + 3 mmHg. These results suggests an interaction between central cholinergic pathways and the angiotensinergic system in the regulation of arterial blood pressure.