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Results for “IONTOPHORESIS”

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At least 667 records · Page 37Linked to original sources
PubMed1978

A gated, high voltage iontophoresis system with accurate current monitoring.

A circuit description for a multichannel constant current source for microiontophoresis is presented. The circuitry allows a high voltage compliance, accurate monitoring of ionotophoretic current without use of batteries, and automatic current neutralization. Drugs may be applied either manually or with an external digital gate signal. A monitor to detect current unbalance greater than a preselected level is also included.

Iontophoresis↗
PubMed1984

Decreased sensitivity of neurons in the basolateral amygdala to dopamine and noradrenaline iontophoresis after a kindling stimulus.

The depressant effects of iontophoretically applied dopamine and noradrenaline on glutamate-induced neuronal firing in the amygdaloid complex of cats were significantly reduced 1 and 2 h after induction of a local epileptiform afterdischarge of the kind used in kindling. Neuronal excitation by glutamate and depression by GABA were not significantly changed. This suggests that kindling is associated with a reduction of the inhibitory effects of endogenous catecholamines.

Amygdala↗
PubMed1981

A high voltage electrometer for recording and iontophoresis with fine-tipped, high resistance microelectrodes.

A high voltage electrometer is described which incorporates a controlled current source, direct current monitoring, balance bridge, electrode resistance, and capacitance compensation test circuits. This device is suitable for making biophysical measurements and iontophoresing dyes or enzymes through extremely fine micropipettes with impedances an order of magnitude higher than conventional micropipettes. Such electrodes are useful for recording from the small neurons of the central nervous system in vivo.

Animals↗
PubMed1993

A tungsten-in-glass iontophoresis assembly for studying input-output relationships in central neurons.

A method is described for the production of an electrode capable of monitoring and modulating the input-output relationship of thalamic neurons. Tungsten-in-glass electrodes were manufactured with the ability to simultaneously record lateral geniculate nucleus action potentials and associated, retinally evoked S-potentials. The recording electrodes were mounted onto multibarreled micropipettes with iontophoretic capability. The completed electrode assembly permitted micropharmacological modulation of the fraction of lateral geniculate nucleus output spikes to retinal input spikes (the transfer ratio). Iontophoretically applied gamma-aminobutyric acid (GABA) decreased the transfer ratio, an effect countered by the GABAA antagonist, bicuculline. Elevated transfer ratios produced by stimulation of an afferent pathway originating in the parabrachial region of the brainstem were decreased by concurrently applied GABA. The fabrication of this electrode assembly employs simple modifications of existing techniques and separate construction of recording and iontophoretic elements to provide high-quality single-unit recordings coupled with micropharmacological function.

Animals↗
PubMed1982

Treatment of chronic pain syndromes with iontophoresis of vinca alkaloids to the skin of patients.

Repeated iontophoretic administration of the microtubule inhibitors vinblastine or vincristine to the segmentally related dermatomes of patients suffering from postherpetic, trigeminal and other neuralgias permanently alleviates chronic, autochthonous pain. The beneficial effect of this therapy is probably due to transganglionic degenerative atrophy of primary central sensory terminals in the Rolando substance by blockade of retrograde axoplasmic transport in sensory nerves.

Adult↗
PubMed2004

Delivery and stability of LHRH and Nafarelin in human skin: the effect of constant/pulsed iontophoresis.

Poor absorption and stability of peptides are the major obstacles concerning the development of therapeutically relevant iontophoretic devices for the transdermal delivery of peptides. The present study examined the impact of constant and pulsed (direct/alternating) current profiles on the transport and stability of two decapeptides LHRH and Nafarelin. The stability of these peptides was studied in a physiological buffer solution, with electrical current, and when the peptide solution was exposed to the stratum corneum or to the epidermal/dermal side of human skin. Pulsed direct current profile was shown to be the most efficient in transporting both LHRH and Nafarelin across the human epidermis. Furthermore, the percentage of intact LHRH in the receiver phase was slightly higher when a pulsed current profile was used. Both the peptides were stable in a physiological buffer and under the influence of current, but LHRH was degraded especially in contact with the dermal side of the skin. Altogether five hydrolytic degradation products of LHRH were observed, and they were identified by LC-ESI/MS and LC-ESI/MS/MS. No degradation products of Nafarelin were observed. It is concluded that the pulsed direct current profile may provide at least a partial solution for the transdermal delivery of peptides in terms of improved transport efficacy and peptide stability.

Administration, Cutaneous↗