A device for beveling fine micropipettes

Proenza, Luis M.; Morton, Ralph E.

doi:10.1016/0031-9384(75)90020-7

Cited by 3 publications

(1 citation statement)

References 7 publications

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“…Beveled glass micropipettes (Proenza and Morton, 1975), filled with an elasmobranch Ringer solution (Cavanaugh, 1975), were used to record the PNR. The pipettes were drawn to a tip diameter of about 1.5/.,m, and beveled on fine lapping paper at an angle of approximately 30 ° to give electrode resistances of 3-7 MI'~.…”

Section: Methodsmentioning

confidence: 99%

The proximal negative response and visual adaptation in the skate retina.

Dowling¹,

Ripps²

1977

The Journal of General Physiology

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A B S T R A C T The proximal negative response (PNR), a complex extracellular potential derived mainly from amacrine cell activity, was studied in the all-rod retina of the skate. Tetrodotoxin (10 -6 mg/ml) did not affect either the waveform or the latency of the response, indicating that the PNR reflects the graded, nonregenerative components of the amacrine cell potential. As regards its adaptive properties, the PNR exhibited both the extreme sensitivity to weak background light and the slow time course of light and dark adaptation that are characteristic of other responses from the proximal retina. Thus, the PNR, like the b-wave and ganglion cell discharge, appears to reflect adaptive processes located within the neural network of the inner retina. I N T R O D U C T I O NIn previous studies we described the adaptive properties of retinal potentials arising f r o m different levels within the all-rod retina of the skate (Dowling and Ripps, 1970, 1971, 1972Green et al., 1975). O u r results suggest that there are two principal stages at which visual thresholds are regulated during light and dark adaptation. One adaptive mechanism is located within the photoreceptors and affects equally the sensitivities of the receptors and the horizontal cells, the other (the "network" mechanism) is located more proximally and exerts its effect on the thresholds for both the b-wave and ganglion cell responses. However, neither the cellular nor the ionic basis of network adaptation has been identified as yet (but cf. Dowling and Ripps, 1976).In an a t t e m p t to f u r t h e r this analysis, we have e x a m i n e d the adaptive characteristics of the proximal negative response (PNR) of the skate retina. Several lines of evidence suggest that this complex retinal potential is mainly the extracellular expression of amacrine cell activity (Burkhardt, 1970; Proenza and B u r k h a r d t , 1973). Because the amacrine cells are in synaptic contact with bipolar and ganglion cells, as well as with other amacrine cells (Dowling and Boycott, 1966), it is i m p o r t a n t to establish the role of these i n t e r n e u r o n s in visual adaptation. We find that the behavior of the PNR during light and dark adaptation resembles in m a n y respects that of the b-wave and ganglion cell discharge. And although there are some small differences a m o n g the adaptive properties of these different responses, we conclude that PNR thresholds, like those of other responses of the proximal retina, are affected by the processes governing network adaptation.

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Section: Methodsmentioning

confidence: 99%

The proximal negative response and visual adaptation in the skate retina.

Dowling¹,

Ripps²

1977

The Journal of General Physiology

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Fabrication of well defined micropipette tips by hydrofluoric acid etching

Muheim

1977

Pflugers Arch.

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Glass tubes were drawn on a two stage pipette puller such that tips with 0.5-2.0 micron inner diameters were obtained as confirmed by scanning electron imaging. The pipettes were attached to an air reservoir with a pressure set at 0.5 bar to prevent fluid from entering the tip. They were lowered into 2% hydrofluoric acid by means of a micromanipulator. When air bubbles began to escape from the tips, they were withdrawn and immersed into 0.5 molar phosphate buffer, pH 7.4, and then rinsed with tap water and ethanol. Etching during 100 s (mean) yielded inner tip diameters of 5 micron (+/- 5% S.D.). The tips were beveled at the same angle at which they had been dipped into the etching fluid. No continuation of the etching process was noticed even after several days.

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Dry beveling of micropipette electrodes

Baldwin

1980

Journal of Neuroscience Methods

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A device for beveling fine micropipettes

Cited by 3 publications

References 7 publications

The proximal negative response and visual adaptation in the skate retina.

The proximal negative response and visual adaptation in the skate retina.

Fabrication of well defined micropipette tips by hydrofluoric acid etching

Dry beveling of micropipette electrodes

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