Search results for "Iontophoresis"
showing 10 items of 68 documents
Brain Distribution and Modulation of Neuronal Excitability by Indicaxanthin From Opuntia Ficus Indica Administered at Nutritionally-Relevant Amounts
2018
Several studies have recently investigated the role of nutraceuticals in complex pathophysiological processes such as oxidative damages, inflammatory conditions and excitotoxicity. In this regard, the effects of nutraceuticals on basic functions of neuronal cells, such as excitability, are still poorly investigated. For this reason, the possible modulation of neuronal excitability by phytochemicals (PhC) could represent an interesting field of research given that excitotoxicity phenomena are involved in neurodegenerative alterations leading, for example, to Alzheimer's disease. The present study was focused on indicaxanthin from Opuntia ficus indica, a bioactive betalain pigment, with a pro…
New prospective in treatment of Parkinson's disease: Studies on permeation of ropinirole through buccal mucosa
2012
The aptitude of ropinirole to permeate the buccal tissue was tested using porcine mucosa mounted on Franz-type diffusion cells as ex vivo model. Drug permeation was also evaluated in presence of various penetration enhancers and in iontophoretic conditions. Ropinirole, widely used in treatment of motor fluctuations of Parkinson's disease, passes the buccal mucosa. Flux and permeability coefficient values suggested that the membrane does not appear a limiting step to the drug absorption. Nevertheless, an initial lag time is observed but the input rate can be modulated by permeation enhancement using limonene or by application of electric fields. Absorption improvement was accompanied by the …
Spreading of sudomotor axon reflexes in human skin.
2005
Acetylcholine (ACh) activates both sudomotor fibers and primary afferent nociceptors. This leads to sudomotor and vasodilator axon reflexes, which can be diminished, for example, in neuropathies. In some neuropathies, however, there is increased axon reflex sweating, a response pattern that has never been observed for vasodilator flares.To compare both types of axon reflexes and to elucidate possible differences.In healthy young male subjects, sweat response and flare reaction in response to ACh were quantified. Constant-current iontophoresis (300 mC) of ACh was performed on the lateral lower legs. The sudomotor axon reflex was visualized with iodine starch staining, and the sweat response …
Somatotopic arrangement of sudomotor axon reflex sweating in humans
2005
Impaired sweating may be one of the first symptoms in neuropathies, and therefore the evaluation of sweating might facilitate their early detection. Sudomotor axon reflexes can be quantified by two different methods: quantitative sudomotor axon reflex testing (QSART) measures the amount of local sweating, whereas staining with the iodine starch reaction assesses the extension of the sudomotor axon reflex area. The aim of our study was to compare both tests at three different sites on the leg: foot, lower leg and thigh.QSART and iodine starch staining after iontophoretic stimulation with acetylcholine were performed on 15 male volunteers (mean age: 25; range 24-27 years) on the left resp. th…
Influence of vagus nerve stimulation on histamine-induced itching
2002
To investigate whether vagus nerve stimulation (VNS) reduces pruritus in humans.Recently, it has been shown that VNS has antinociceptive and antidepressant effects in humans.Eleven patients were investigated before (baseline) and during chronic VNS treatment. The experiments were performed at two different stimulation intensities: 2 to 5 days after implantation at a low stimulation intensity (mean intensity 0.7 +/- 0.2 mA, second session) and after 8 to 14 weeks of VNS therapy (mean intensity 1.4 +/- 0.3 mA, third session). Twelve healthy age- and sex-matched subjects were investigated using the same experimental protocol. Itch was induced by histamine-iontophoresis and quantified on a visu…
Transdermal nortriptyline hydrocloride patch formulated within a chitosan matrix intended to be used for smoking cessation.
2010
The aim of this study was to prepare and characterize both physically and biopharmaceutically, a nortriptyline hydrochloride (NTP-HCl) patch formulated in chitosan.16 g of each chitosan patch formulation (I, II and III, see Table 1 ) was poured onto rectangular glass plates (64 cm²) at a height of 1 mm and dried for 24 h at room temperature. In order to characterize the chitosan patches, polarized microscopy, in vitro skin permeation studies by passive diffusion and iontophoresis and rheological and bioadhesion studies were performed.Polarized microscopy revealed the absence of aggregates and crystal forms of NTP-HCl in all transdermal patches after 30 days of storage. The rheological behav…
Enhancement of nortriptyline penetration through human epidermis: influence of chemical enhancers and iontophoresis.
2008
Abstract Different known percutaneous chemical enhancers and iontophoresis have been tested in-vitro to study their ability to increase transdermal absorption of nortriptyline hydrochloride (20 mg mL−1). The chemicals 1-dodecanol, Span 20, Azone, (R)-(+)-limonene or isopropyl myristate were used as an overnight pretreatment at 5% (w/w) in ethanol. Furthermore, isopropyl myristate (20%, w/w) and propylene glycol (15%, w/w) were tested in the same vehicle. Iontophoresis was applied directly to the nortriptyline hydrochloride donor solution for three different concentrations (20, 2 and 0.5 mgmL−1). The chemical enhancers slightly increased the nortriptyline transdermal flux but iontophoresis w…
Unit study in cat claustrum of the effects of iontophoretic neurotransmitters and correlations with the effects of activation of some afferent pathwa…
1982
Glutamate (Glut), acetylcholine (ACh) and dopamine (DA) were iontophoretically applied on cat claustral neurons. Glut did not affect all the neurons; ACh had both excitatory and inhibitory effects, while DA was prevalently inhibitory. An analysis was made of the time-course of excitatory and inhibitory responses on the basis of the mean firing rate variations during and after ACh and DA release. Three types of responses are described for each drug: short lasting inhibition, long lasting inhibition and long lasting excitation. The experimental data were statistically elaborated. The effects of ACh and of DA were compared with those of activation obtained by sensorial peripheric and thalamic …
Noninvasive sampling of phenylalanine by reverse iontophoresis.
1999
While iontophoresis is typically associated with drug delivery across the skin, the symmetry of the technique permits its application to the essentially noninvasive withdrawal of biologically important analytes from the subcutaneous space to the body's surface. The identification of other substances which can be monitored by this procedure, and to its optimization and development as a more general clinical chemistry tool, is a long-term objective. In this paper, we describe a preliminary in vitro investigation into the feasibility of extracting and analyzing the amino acid, phenylalanine, with the ultimate aim to develop a diagnostic test for phenylketonuria, a potentially fatal metabolic d…
Electrophysiological and microiontophoretic analysis of the habenulo-hippocampal circuit.
1991
In the cat, the effects of lateral habenula stimulation, at different ranges of frequency, on hippocampal units were studied. Habenular stimulation at low frequency excited, while at high frequency inhibited the greater part of hippocampal units. Moreover, in order to clarify the possible pathway involved in the habenulo-hippocampal circuit, the effects of iontophoretic acetylcholine and serotonin on hippocampal units were compared with those of habenular stimulation. Iontophoretic acetylcholine induced both excitatory and inhibitory responses while serotonin induced only inhibitory responses. Iontophoretic atropine blocked the effects of acetylcholine ejection but did not antagonize stimul…