New line after paragraph heading

[Jonathan Ware]

Hello,

I am writing a document using the Article document style.  Following a
paragraph (or subparagraph) heading, the text is placed on the same
line.  Forcing a line break (ctrl-enter) works but the text is then
indented.  Is there any way I put the text following the heading on a
new line without indentation?

Thanks in advance for any help.

Jonathan