[Nombres]
Adrian
Alfoso
Saul
Diana
Juan
Ramon

Try
        RSSelect.Open("SELECT ...", ConnSql3, CursorTypeEnum.adOpenStatic, LockTypeEnum.adLockOptimistic)
        Dim colcombo As DataGridViewComboBoxColumn = CType(DataGridView1.Columns("ResponsableCortoPlazo"), DataGridViewComboBoxColumn)

        For i = 1 To RSSelect.RecordCount
            colcombo.Items.Add(RSSelect.Fields(0).Value)
            RSSelect.MoveNext()
        Next
    Catch ex As Exception
        RSSelect.Close()
        MessageBox.Show("Error: " & ex.Message)
    End Try
    RSSelect.Close()

Try
        RSBuscar.Open("Select ...", ConnSql3, CursorTypeEnum.adOpenStatic, LockTypeEnum.adLockOptimistic)
        If RSBuscar.EOF Then
            Me.DataGridView1.Rows.Add()
            oMCColBut.Visible = False
            RSBuscar.Close()
        Else
            For i = 1 To RSBuscar.RecordCount

                DataGridView1.Rows.Add(RSBuscar.Fields(2).Value, RSBuscar.Fields(3).Value, RSBuscar.Fields(5).Value,
                                        RSBuscar.Fields(0).Value, RSBuscar.Fields(6).Value, RSBuscar.Fields(4).Value)
                RSBuscar.MoveNext()

            Next

            RSBuscar.Close()

        End If
    Catch ex As Exception
        MsgBox(ex.Message)
    End Try