Activation of membrane receptors by neurotransmitter released from temperature-sensitive hydrogels

The present paper describes the design, construction and testing of a temperature-sensitive N-isopropylacrylamide hydrogel device for studying the controlled presentation of γ-aminobutyric acid (GABA) to GABAC membrane receptors expressed in Xenopus laevis oocytes. Upon temperature lowering, the GABA-loaded hydrogel positioned near the surface of the GABAC-expressing oocyte elicits a membrane current response resembling that induced by superfusion of the oocyte with free GABA. The response to cooling is not observed when GABA is omitted from the hydrogel loading solution. In addition, picrotoxin, a known GABAC receptor antagonist, inhibits the oocyte membrane current response associated with temperature lowering of GABA-loaded hydrogels. The data indicate that the present system affords a temperature-regulated release of GABA from the hydrogel and a resulting activation of the expressed GABAC receptors.