?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(dot)bath(at)unix(dot)net