Receptor: 1. In cell biology, a structure on the surface of a cell (or inside a cell) that selectively receives and binds a specific substance. There are many receptors.
The most common is EPNS (Electro Plated Nickel Silver) but many other symbols are used: 1  EPBM (Electro Plated Britannia Metal). 2  EPCA (Electro Plated Copper Alloy). 3  ESM (Electro Plated Silver Mounts).he most common is EPNS (Electro Plated Nickel Silver) but many other symbols are used: 1  EPBM (Electro Plated Britannia Metal). 2  EPCA (Electro Plated Copper Alloy). 3  ESM (Electro Plated Silver Mounts).
IPN is a message service that sends you a notification when any type of transaction occurs in your account. The messages are received and processed by your server(s). To receive and process Instant Payment Notification (IPN) messages: Create an IPN listener to receive and process the IPN messages sent by PayPal. For complete details on creating an IPN listener, see Implementing an IPN Listener.