Dear Dr. ***,

Your manuscript no. M***, entitled: Title

has been evaluated. Unfortunately, the comments of only one referee are available and since we do not wish to delay the processing of the manuscript, our decision is based on these comments. The referee raised a munber of important points, as can be seen from the enclosed evaluation sheet.

I am sorry to inform you that we have therefore decided that, in its present form, this manuscript cannot be accepted for publication in the Joumal.

If you are wining to alter the manuscript according to the comments made by the referee, we shall be glad to reconsider it for publication. Furthermore, we inform you that, in case a checklist is included, the points in this checklist should be taken care of.

Please reply to the comments of the referee and indicate which of the required changes have been made and where these changes are to be found in the revised manuscript (page and line). We also ask you to give the reasons that led you to reject some of the suggested changes

.

Would you please send us the manuscript in duplicate, i.e. the entire revised manuscript and one copy thereof, including the complete set of illustrations and list of references for the manuscript and for the copy. Your reply to the comments made by the referee, also in duplicate, should accompany the manuscript.

Yours sincerely,

Referee's comments

This paper presents interesting data providing pharmacological evidence for mechanisms involved in [Ca]i oscillations in living cells. The differential effects of protein kinase influencing drugs in this regard are of potential interest. The technique used by the authors is sound, but the interpretation of the data in relation to SERCA pumps deserves more caution since the IP3-receptor and plasmamembrane Ca-channels may be affected as well by the drugs used (as shown for thapsigargin).

Detailed comments:

- As title I would suggest "Title".

- As the authors do their experiments in the presence of extracellular Ca, it is difficult to discriminate between effects of drugs on Ca-ATPase, IP3-mediated Ca-mobilization and Ca-entry as a result of depleting intracellular stores. This is important because of reported phosphorylation of the IP3-receptor by PKC, PKA as well as CaM kinase. Experiments in the absence of extracellular Ca and with heparin should give more clarity about the mechanism(s) involved.

- The authors should use "SERCA-pumps" instead of "Ca-pumping" in the discussion to discriminate between the intracellular and plasmamembrane-located Ca-ATPases.

- The authors did not show effects of thapsigargin in Fig. IA. although they refer to it in the text.

- The spontaneous effect of I ｵM CPA on [Ca]i could be explained by inhibition of the plasmamembrane Ca-pump. The authors did not discuss this observation.

- Effects of drugs on ATP-induced [Ca]i-oscillations are generally indicated in the text as being "plateau-like" which is, however, not always the case. CPA and PKI induce transient [Ca]i-elevations, sometimes reaching a submaximal plateau. The authors should discuss these apparent differences.

- The authors should recheck the text with respect to the english. for example at a room temperature (page 4), all of Ca2+-mobilizing signal (page 8), As it was only the Ca-ATPases (page 8).

- The Biochem. J. issue and pages of ref. Authors et al. 1993c are missing.