Sending slug in route using post in form

I am trying to send {slug} in route:

Route::post('page-edit/{slug}', 'PageController@postSavePage');

in view I have:

{!! Form::open(array('action' => 'PageController@postSavePage')) !!}

in controller:

public function postSavePage($slug = null){
dd($slug);
}

but I have error:

Missing required parameters for [Route: ] [URI: page-edit/{slug}]. (View: /var/www/html/CMS/resources/views/admin/pages/page-edit.blade.php)

What is the correct syntax?

via Chebli Mohamed