How to get description of table field in trigger

Hello All!

There is a table:

CREATE TABLE "base" (
"id" int4 DEFAULT nextval('base_id_seq'::text) NOT NULL,
"field" text NOT NULL,
"field_m" text NOT NULL,
"field_n" text NOT NULL
);

COMMENT ON TABLE base IS 'base table';
COMMENT ON COLUMN base.field_m IS 'monitor';

CREATE FUNCTION archive() RETURNS opaque AS '
END;
' LANGUAGE 'plpgsql';

CREATE TRIGGER "archive" AFTER UPDATE
ON base FOR EACH ROW
EXECUTE PROCEDURE archive();

Is there a method to get descriptions of the fields in TABLE base in my function archive?

I found col_description(tableOID, columnnumber) but I can't understand how to use it.
How to get tableOID in my function?

--
with respection Andrey Feofilactovich.
e-mail: feo(at)ttn(dot)ru, feo(at)feo(dot)org(dot)ru
ICQ: 28073807