?Equiv to oracle (ENABLE|DISABLE) (CONSTRAINT|TRIGGER) statements?

Folks,

Summary: Does postgresql have equivalents to the following Oracle statements?   DISABLE CONSTRAINT ...   ENABLE CONSTRAINT ...   DISABLE TRIGGER ...   ENABLE TRIGGER ...

Background: One of the advantages of Oracle over some competitors such as MS-SQL and Sybase is the ability to toggle a constraint or trigger on and off, without blatting it, and without the hassle of finding any code and any accessory information (like comments, permissions...).
 BTW, I personally put C-style comments at the front of the clause so I can get the why's/how's into the syscatalogs - but I wear jackboots where documentation is concerned :-) and get at these for autodoccing and/or generation of meaningful messages to users when raising exception messages from the server.
 This capability is especially useful when there is some disgusting data-munging by a DBA, not just for import/export.
 I've tried grovelling through the sql from a pg_dump invoked with --disable-triggers, but it has no enable/disable triggers or constraints, merely creating primary/foreign constraints AFTER issuing the COPY.
 Yep, I'd expect this ONLY to work when issued by someone with DBA privs (and maybe the target object owner, although I imagine reasons that /might/ be a bad idea for paranoid info management governance).

Thanks in advance
-- 
David T. Bath
dave.bath@unix.net