1 Describe how the Voltage Clamp and Patch Clamp recording t

1) Describe how the Voltage Clamp and Patch Clamp recording techniques along with similar methods, can be used to identify and study ionic current flow in tissue

Solution

The study of the ionic current flow in tissue and cells within living organism is known as electrophysiology. Neurons are the units which help in conduction of electrical activity and generates action potential. The flow of ions or current flow in tissue takes place through some gated channel and is important in order to transmit nerve impulse. The neurons communicate with each other and generate a signal using the electrical activity initiated by flow of ions. In order to understand our nervous system, stimulation of action and signalling mechanism, it is integral we understand, identify and study the flow of ions in tissue. With this study, we are able to decode the pathway of signalling molecules and various other reactions.

All the cells membranes have different ion channels embedded on their membrane and for neurons the number of these ions channels is more. A cell requires the movement or flow of ions across it to leading to change in resting membrane potential. The change is important for transmitting signals that is facilitated by neurons.

Methods used for identifying and studying the flow of ions via tissue

There are various ways and methods using which we can find out the pattern of ion flow in tissue. Let us discuss two methods that are exclusively used for studying the ionic current flow in tissues.

Patch Clamp

The method is used in studying single or mutiple ion channels present in a cell or tissues. As the method has helped in understanding the route of ion flow, it has successfully helped in improving the understanding of cardiac and nervous system related ailments and diseases. In the patch clamp method, it generally helps in study of individual ion channels in a patch of cell membrane. Since it concentrates only on single or small set of ion channels, it is mostly used in studying the excitable cells like muscle fibres, neurons, cardiac cells etc. The discovery of this technique for measuring and identifying flow of ions can be credited to Neher and Sakmann.

How the Technique is utilised

Patch Clamp Technique is used to understand about neural transmissions and how neurons react on releases of transmitters. It gives us an idea about activity of specific ion channel on a cell membrane as well as how a cell behaves in response to closing and opening of ion channels. The major difference from voltage clamp lies in the fact that patch clamp is used to study small patch of membrane.

Steps of the technique

The method can be used to individually study the characteristics response of different channel and their pattern of opening and closing.

Voltage Clamp Method

The voltage clamp method was discovered by Kenneth Cole in 1940s and is a method to measure the voltage across a cell membrane. It helps in measuring the ion currents across the membranes of cells like neurones. The action potential arises across the cell due to co-ordinated movement of potassium and sodium. The voltage clamp technique controls the voltage to a set value and is thus used to study the changes in sodium and potassium conductance that occur within a stipulated timeframe.

It helps in studying of conductance of potassium and sodium over time. The squid giant axon neurons are studied using the method

Technique