Search results for "Calcium Channel"

2019

AbstractDuring early postnatal life, speed up of signal propagation through many central and peripheral neurons has been associated with an increase in axon diameter or/and myelination. Especially in unmyelinated axons postnatal adjustments of axonal membrane conductances is potentially a third mechanism but solid evidence is lacking. Here, we show that axonal action potential (AP) conduction velocity in theDrosophilagiant fiber (GF) interneuron, which is required for fast long-distance signal conduction through the escape circuit, is increased by 80% during the first day of adult life. Genetic manipulations indicate that this postnatal increase in AP conduction velocity in the unmyelinated…

Central action of cinnarizine and flunarizine: A saccadic eye movement study

1994

The mechanism of action of flunarizine (FZ) and cinnarizine (CZ) on the CNS is not fully understood. Computer analysis of saccadic eye movements (SEM) provides a sensitive and objective method for evaluating drug effect on the function of specific brain structures. This study aimed to assess the effect of a single oral dose of FZ (20 mg) and CZ (150 mg) on CNS function by means of computer analysis of SEM. Ten healthy volunteers were studied according to a double-blind, cross-over, placebo-controlled design. Peak saccadic velocity (PSV), which is related to the function of a specific group of burst neurons located in the brain stem, was significantly reduced by FZ. No significant effect of …

Identification and expansion of human osteosarcoma-cancer-stem cells by long-term 3-aminobenzamide treatment

2009

A novel cancer stem-like cell line (3AB-OS), expressing a number of pluripotent stem cell markers, was irreversibly selected from human osteosarcoma MG-63 cells by long-term treatment (100 days) with 3-aminobenzamide (3AB). 3AB-OS cells are a heterogeneous and stable cell population composed by three types of fibroblastoid cells, spindle-shaped, polygonal-shaped, and rounded-shaped. With respect to MG-63 cells, 3AB-OS cells are extremely smaller, possess a much greater capacity to form spheres, a stronger self-renewal ability and much higher levels of cell cycle markers which account for G1-S/G2-M phases progression. Differently from MG-63 cells, 3AB-OS cells can be reseeded unlimitedly wit…

Cyclosporin- and nifedipine-induced gingival overgrowth in renal transplant patients: correlations with periodontal and pharmacological parameters, a…

1996

The factors associated with cyclosporin A (CsA)- and nifedipine (Nif)-induced gingival overgrowth were investigated in 113 renal transplant recipients receiving CsA alone (Group 1) [n = 61], CsA and Nif (Group 2) [n = 28], or azathioprine (Aza) (Control Group) [n = 24]. Periodontal and pharmacological parameters were assessed for each patient. The patients with a gingival overgrowth index (GOI) score1 were considered responders (R); those with a score/= 1 were non-responders (NR). Gingival overgrowth occurred in 33.7% of the patients in Groups 1 and 2; 60% of the responders were receiving CsA+Nif. In R, no relationship was found between the GOI and the periodontal and pharmacological parame…

Positive inotropic response to 5-HT in human atrial but not in ventricular heart muscle

1992

The effects of 5-hydroxytryptamine (5-HT) on force of contraction (FC), action potential (AP) and calcium current (ICa) were studied in human right atrial and left ventricular heart muscle. 5-HT exerted a concentration-dependent increase in FC in multicellular atrial preparations; the EC50 was approximately 3 x 10(-7) mol/l. Maximal increases in FC (252 +/- 58% of control values; mean +/- SEM, n = 6) were obtained at 5-HT 10(-5) mol/l. At this concentration, ICa was increased four- to sevenfold in enzymatically isolated atrial myocytes. In contrast, ventricular preparations did not respond to 5-HT; FC, AP and ICa remained unaffected. In the same preparations, FC was increased by isoprenalin…

Vasopressin receptors involved in adrenergic neurotransmission in the circular muscle of the human vas deferens

1998

We studied the effects of vasopressin on the adrenergic responses of in vitro preparations of circular muscle from the vas deferens obtained from 28 men undergoing elective vasectomy. Vasopressin (3 x 10(-9)-3 x 10(-8) M) enhanced the phasic contractions elicited by electrical field stimulation and noradrenaline. This potentiation was blocked by the vasopressin V1 receptor antagonist d(CH2)5Tyr(Me)vasopressin (10(-6) M) but not by the vasopressin V2 receptor antagonist [d(CH2)5, D-Ile2,Ile4,Arg8]vasopressin (10(-6) M). The Ca2+ antagonist nifedipine (10(-6) M) did not affect the potentiation of electrical field stimulation induced by vasopressin and noradrenaline but reduced KCl-induced con…

The Interaction of Buccal Mucosal Epithelial Cells with E. coli Bacteria Enhances the Intraepithelial Calcium Flux and the Release of Prostaglandin E…

1999

Mucosal epithelial cells contribute significantly to host defense mechanisms. Uroepithelial cells (UEC) from healthy donors suppress bacterial growth in vitro. Bacterial adherence to UEC has been shown to be a prerequisite. Similar results have been shown for buccal epithelial cells (BEC). The host response triggered by the host-parasite interaction seems to involve signal transduction and intracellular activation of second messengers. In this study the intraepithelial calcium flux was analyzed in individual BEC after bacterial contact. BEC were derived from scrapes of the buccal mucosa and labelled with fluo-3 (a calcium indicator). Thereafter the cells were analyzed immediately with a FAC…

Role of endothelium and calcium channels in endothelin-induced contraction of human cerebral arteries

1990

Endothelin constricted human isolated cerebral arteries in a concentration-dependent manner. The maximal tension developed, as well as EC50 values were similar in arteries with and without endothelium. Removal of extracellular calcium or addition of the calcium antagonist nicardipine (10(-6)M), attenuated but did not abolish responses to endothelin. These experiments show that the endothelin-induced contraction in human cerebral arteries is not linked to the presence of intact endothelial cells. The data also show that the contractile effects of endothelin cannot be explained solely by an action on voltage-dependent calcium channels.

Factors Related to the Occurrence of Microalbuminuria During Antihypertensive Treatment in Essential Hypertension

2002

The objective of the study was to assess the factors related to the occurrence of microalbuminuria during the follow-up of a young adult group with essential hypertension that had not been previously treated. Normo-albuminuric essential hypertensives, <50 years old, who had not been previously treated with antihypertensive drugs and who did not have diabetes mellitus were included. After the initial evaluation, patients were treated using only nonpharmacological measures (n=62), β-blockers (n=38), ACE inhibitors (n=64), calcium channel blockers (n=8), and several classes (n=15). Measurements were taken for office blood pressure, biochemical profile, and 24-hour urinary albumin excretion…

Determinants of urinary albumin excretion reduction in essential hypertension: A long-term follow-up study.

2006

The objective of the present study was to assess factors related to long-term changes in urinary albumin excretion (UAE) of nondiabetic microalbuminuric (n = 252) or proteinuric hypertensive individuals (n = 58) in a prospective follow-up.After enrollment, patients were placed on usual care including nonpharmacological treatment and/or treatment with an antihypertensive drug regime to achieve blood pressure135/85 mmHg. Periodic UAE measurements were performed until regression or significant reduction (defined when UAE dropped50% from the initial values, plus reduction of UAE to30 mg/24 h for microalbuminuric patients and300 mg/24 h for proteinuric patients).Among the microalbuminuric patien…