Posted by:
WK
at Thu Dec 11 13:55:38 2003 [ Email Message ] [ Show All Posts by WK ]
>>PHOSPHOLIPASE A - Promotes histamine production in tissue. Also probably largely responsible for the "shock factor" encountered in snakebite. (S/E: Black Mamba, Taipan, cottonmouth)
Hi Wolfgang,
I believe the thinking behind that quote dates to the 1940’s when histamine was felt to be the major mediator of shock. It was during this period that researchers were using snake venoms to study inflammatory mechanisms and their roles in producing shock. Recall that the term “shock”, in a clinical context, describes a state in which there is inadequate supply of blood / oxygen to vital organs due to a severe disturbance in blood volume, blood location, or blood pumping (or a combination of these). Blood pressure is the most easily measurable marker to determine presence or absence of shock. Anyhow, in these early investigations into inflammation / shock, certain snake venoms were shown to cause hypotension / shock in animals, and analysis of venous blood from “venom-shocked” animals consistently showed elevated histamine levels, suggesting histamine might play a role in shock, and that venoms contained histamine releasing activity. Later experiments showed certain PLA2s in certain venoms produce mast cell degranulation in a nonspecific fashion. I suspect this is why phospholipase (or perhaps even histamine) is referred to as “shock factor” in the old excerpt provided by Bud.
Budman, from where did you get that excerpt, if you don’t mind me asking?
Cheers,
WK
[ Hide Replies ]
- Venom questions for the experts - budman 1st, Tue Dec 9 16:55:03 2003
- Mirror,mirror - Deuce, Tue Dec 9 20:41:40 2003
- RE: Mirror,mirror - budman 1st, Tue Dec 9 21:39:58 2003
- ok whats what? - budman 1st, Tue Dec 9 21:43:43 2003
- RE: ok whats what? - Deuce, Wed Dec 10 08:41:12 2003
- cool - budman 1st, Wed Dec 10 16:51:54 2003
- RE: cool - nobites, Wed Dec 10 17:42:39 2003
- ok - budman 1st, Wed Dec 10 18:32:07 2003
- more - budman 1st, Wed Dec 10 18:53:08 2003
- true, but.. - nobites, Wed Dec 10 22:15:41 2003
- and - budman 1st, Thu Dec 11 04:08:52 2003
- RE: Venom questions for the experts - WW, Wed Dec 10 04:33:55 2003
- once again WW thanks - budman 1st, Wed Dec 10 16:27:34 2003
 "Shock Factor" - WK, Thu Dec 11 13:55:38 2003
- RE: Venom questions for the experts - BGF, Wed Dec 10 21:24:26 2003
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