Fig. 2.
![Fig. 2. Calcium responses in platelets are due to the proteolytic activity of the enzymes and can be desensitized with thrombin. / The [Ca++]i responses in platelets to: (A) 0.5 nM HRgpA inactivated with leupeptin; (B) 0.5 nM HRgpA, both followed by the addition of 2 μM antipain, 50 nM thrombin, and treatment with 60 μM ADP; (C) 25 nM RgpB inactivated with leupeptin, followed by 10 nM thrombin; (D) 25 nM RgpB, followed by 10 nM thrombin. The [Ca++]i responses shown are those for 1 of the 4 donors in which these effects were observed. Antipain (2 μM) was added in between the HRgpA and thrombin to ensure that the cysteine protease was not desensitizing responses by cleaving thrombin.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/97/12/10.1182_blood.v97.12.3790/6/h81211171002.jpeg?Expires=1726834331&Signature=ni0cdU6GHdnyn4TTkz5Am7~isCeCLv3B9hiwjvJIuAF~ZBJ-Xy~owUUDOJe4EgcJHK4ITI51G2yoHVL8bP~ua75797exQXS5uYniuWXl~WP0h6f1aIzi5Kysku4c8jKZKKCsyq5A4N8D50fEx3EMSaRl-A1O6XpIyMzSlkjhoJ9JjGnP2fuwdYFXFx6QjLzNCB6oHj69PFzL-~dSEcAWsuk~Pn~1tlxtauR1itYX3Aczpt~yuwoJAXg7~5voUmIzXdLWqg2FwdhI97i2BMM6E-pZyCwtejI9Yt1qqIo0KIRbykUJWhVJOa1A7iuzktOGqmpNE5-lIBfwNleTpTEquw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
Calcium responses in platelets are due to the proteolytic activity of the enzymes and can be desensitized with thrombin.
The [Ca++]i responses in platelets to: (A) 0.5 nM HRgpA inactivated with leupeptin; (B) 0.5 nM HRgpA, both followed by the addition of 2 μM antipain, 50 nM thrombin, and treatment with 60 μM ADP; (C) 25 nM RgpB inactivated with leupeptin, followed by 10 nM thrombin; (D) 25 nM RgpB, followed by 10 nM thrombin. The [Ca++]i responses shown are those for 1 of the 4 donors in which these effects were observed. Antipain (2 μM) was added in between the HRgpA and thrombin to ensure that the cysteine protease was not desensitizing responses by cleaving thrombin.
