Figure 3.

Desensitization of PAR1 and PAR4 ablates calcium signals in response to thrombin. A. Increase in [Ca]_i recorded as in Fig. 2. Calcium increase elicited by application of PAR1-AP completely desensitizes response to a subsequent application of PAR1-AP but not to PAR4-AP. The calcium signal in response to thrombin was ablated in the large majority of cells by desensitization of both PAR1 and PAR4. All experimental details as in Fig. 2.

B. Following desensitization of PAR1 and PAR4 only 1.6% of neurons gave a calcium signal in response to thrombin, compared with 15.2% in control neurons. Summary of results from n = 187 neurons from 4 separate coverslips.