Exhibit 4.10



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                        FIRST AMENDMENT TO LOAN AGREEMENT



                          Dated as of February 1, 2004

                                     Between

         STATE ENVIRONMENTAL IMPROVEMENT AND ENERGY RESOURCES AUTHORITY



                                       and



                      UNION ELECTRIC COMPANY, DBA AMERENUE
                  ---------------------------------------------
                     Supplementing and amending that certain
                                 Loan Agreement
                          dated as of December 1, 1992


                                   $47,500,000
         State Environmental Improvement and Energy Resources Authority
                Environmental Improvement Revenue Refunding Bonds
                        (Union Electric Company Project)
                                   Series 1992
                  ---------------------------------------------






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<PAGE>



                        FIRST AMENDMENT TO LOAN AGREEMENT
                            ------------------------


                                TABLE OF CONTENTS

  (This Table of Contents is not a part of the First Amendment to Loan Agreement
                   and is only for convenience of reference.)

<TABLE>
<CAPTION>

SECTION                                                HEADING                                                 PAGE
<S>   <C>                 <C>
ARTICLE I                  DEFINITIONS............................................................................1

       Section 1.01.       Definitions of Terms...................................................................1

ARTICLE II                 AMENDMENTS TO ORIGINAL AGREEMENT.......................................................2

       Section 2.01.       Amendment to Article III of the Original Agreement.....................................2
       Section 2.02.       Amendments to Article V of the Original Agreement......................................2
       Section 2.03.       Amendments to Article VI of the Original Agreement.....................................5
       Section 2.04.       Amendment to Section 8.1 of the Original Agreement.....................................7
       Section 2.05.       Amendments to Article IX of the Original Agreement.....................................7
       Section 2.06.       Amendments to Article X of the Original Agreement......................................7

ARTICLE III                MISCELLANEOUS..........................................................................8

       Section 3.01.       Agreement Confirmed....................................................................8
       Section 3.02.       Severability...........................................................................8
       Section 3.03.       Counterparts...........................................................................8
       Section 3.04.       Applicable Provisions of Law...........................................................8
       Section 3.05.       Effective Date.........................................................................8

</TABLE>

                                       i

<PAGE>



                        FIRST AMENDMENT TO LOAN AGREEMENT

     THIS FIRST AMENDMENT TO LOAN AGREEMENT (this "First Amendment") is made and
entered into as of February 1, 2004 between the STATE ENVIRONMENTAL  IMPROVEMENT
AND ENERGY  RESOURCES  AUTHORITY of the State of Missouri,  a body corporate and
politic  and a  governmental  instrumentality  of the  State  of  Missouri  (the
"Issuer"),  and UNION ELECTRIC COMPANY, a Missouri corporation doing business as
AMERENUE (the "Company"):


                                   WITNESSETH:

     WHEREAS,   on  December  3,  1992  the  Issuer  issued  its   Environmental
Improvement Revenue Refunding Bonds (Union Electric Company Project) Series 1992
(the "Bonds") in the original aggregate principal amount of $47,500,000 pursuant
to an Indenture of Trust dated as of December 1, 1992 (the "Original Indenture")
by and between the Issuer and UMB Bank & Trust,  N.A.,  successor to  Mercantile
Bank of St. Louis National Association (the "Trustee"); and

     WHEREAS,  in connection with the issuance of the Bonds,  the Issuer and the
Company  executed and delivered the Loan Agreement  dated as of December 1, 1992
by and between the Issuer and the Company (the "Original Agreement"); and

     WHEREAS,  the  Original  Indenture  is being  amended  and  restated by the
Amended and Restated Indenture of Trust of even date herewith in order to secure
the Bonds with additional  collateral,  i.e., the Bond Insurance  Policy and the
Company's Mortgage Bonds; and

     WHEREAS,  Section 11.02 of the Original  Indenture provides that the Issuer
and the  Company  may,  with  the  consent  of the  Bondholders,  enter  into an
agreement  supplemental  to the  Original  Agreement  and  Section  10.4  of the
Original Agreement  provides that such supplemental  agreement is subject to the
written consent of the Trustee; and

     WHEREAS,  the  Issuer  and the  Company  desire to enter  into  this  First
Amendment,  as permitted by Section 11.02 of the Original  Indenture and Section
10.4 of the Original Agreement, in order to amend the Original Agreement to make
certain  changes  relating  to  the  amendments  being  made  to  the  Indenture
concurrently herewith;

     NOW,  THEREFORE,  in  consideration  of the  foregoing  and  of the  mutual
covenants herein set forth, the parties hereto agree as follows:


                                    ARTICLE I

                                   DEFINITIONS

        Section 1.01. Definitions of Terms. For all purposes of this First
Amendment, in addition to the terms defined above in the WHEREAS clauses, unless
the context clearly requires otherwise, all terms defined in Article I of the
Indenture have the same meanings in this First Amendment.

<PAGE>

                                   ARTICLE II

                        AMENDMENTS TO ORIGINAL AGREEMENT

     Section 2.01. Amendment to Article III of the Original Agreement.  The last
clause of Section 3.5 of the  Original  Agreement  is hereby  amended to read as
follows:

               ", provided that the Trustee and the Bond Insurer receive a
          Favorable Opinion of Tax Counsel prior to such abandonment."

     Section  2.02.  Amendments  to  Article V of the  Original  Agreement.  (a)
Subsection  5.1(a)  of the  Original  Agreement  is  hereby  amended  to read as
follows:

                    "(a)  The  Company  will  repay  the  loan  made to it under
               Section 4.1 as follows:  Before the close of business (local time
               at the principal  corporate  office of the  Registrar) on the day
               before  each day on which any payment of either  principal  of or
               interest  on the Bonds,  or both,  shall  become due  (whether at
               maturity,  or upon redemption or acceleration or otherwise),  the
               Company  will pay,  in  immediately  available  funds,  an amount
               which,  together with other moneys held by the Tender Agent or by
               the Trustee  under the Indenture  and  available  therefor,  will
               enable  the  Registrar  to make such  payment in full in a timely
               manner.  If such day on which any payment shall become due is not
               a Business Day,  then the payment  required by this Section shall
               be made on or before the  preceding  Business Day. If the Company
               defaults in any payment  required  by this  Section,  the Company
               will pay interest  (to the extent  allowed by law) on such amount
               until paid at the rate provided for in the Bonds."

               (b)  The last paragraph of Section 5.1 of the Original  Agreement
          is hereby amended to read as follows:

                    "All amounts  payable  under this Section by the Company are
               assigned by the Issuer to the Trustee  pursuant to the  Indenture
               for the  benefit of the  Bondholders  and the Bond  Insurer.  The
               Company  consents to such  assignment.  Accordingly,  the Company
               will pay  directly to the  Registrar at its  principal  corporate
               trust office all payments payable by the Company pursuant to this
               Section."

               (c)  There is hereby added a new  paragraph to the end of Section
          5.1 of the Original Agreement to read as follows:

                    "The  Company  agrees to make all  payments  when due on the
               First  Mortgage  Bonds.  If for any  reason  amounts  paid to the

                                      -2-

<PAGE>

               Trustee on the First Mortgage  Bonds,  together with other moneys
               held by the Trustee and available for that purpose,  would not be
               sufficient  to make the  corresponding  payments of principal of,
               premium,  if any, and interest on the Bonds corresponding to such
               First Mortgage  Bonds when such payments  become due, the Company
               will pay the  amounts  required  from time to time to make up any
               such deficiency."

               (d)  A new  Subsection  5.2(d)  is  hereby  added  to the  end of
          Section 5.2 of the Original Agreement to read as follows:

                         "(d)   Notwithstanding  any  provision  herein  to  the
                    contrary,  payment to the Bond  Insurer of all  amounts  due
                    under the Insurance  Agreement  pursuant to the terms of the
                    Insurance Agreement."

               (e)  Section 5.3 of the Original  Agreement is hereby  amended to
          read as follows:

                         "Section 5.3. Prepayments.  The Company may at any time
                    prepay  to the  Registrar  all or any  part  of the  amounts
                    payable under Section 5.1. A prepayment will not relieve the
                    Company of its  obligations  under this Loan Agreement until
                    all the Bonds have been paid or provision for the payment of
                    all the Bonds has been made in accordance with the Indenture
                    and all amounts due the Bond Insurer have been paid.  In the
                    event of a mandatory  redemption  of the Bonds,  the Company
                    will prepay all amounts necessary for such redemption."

               (f)  Section 5.4 of the Original  Agreement is hereby  amended to
          read as follows:

                         "Section 5.4. Obligations of Company Unconditional. The
                    Company  agrees that the  obligations of the Company to make
                    the payments required by Sections 5.1 and 5.3 and to perform
                    its other agreements  contained in this Loan Agreement shall
                    be absolute and  unconditional.  Until the  principal of and
                    interest  on the  Bonds  shall  have  been  fully  paid,  or
                    provision  for the  payment of the Bonds made in  accordance
                    with the  Indenture,  and the Bond  Insurer is paid in full,
                    the Company (a) will not suspend or discontinue any payments
                    provided  for in Section 5.1, (b) will perform all its other
                    agreements in this Loan Agreement and (c) will not terminate
                    this  Loan  Agreement  for any cause  including  any acts or
                    circumstances  that may constitute failure of consideration,
                    destruction   of  or  damage  to  the  Project,   commercial
                    frustration of purpose, any change in the laws of the United
                    States  or of the  State  or any  political  subdivision  of
                    either or any  failure of the  Issuer to perform  any of its
                    agreements,   whether  express  or  implied,  or  any

                                      -3-

<PAGE>

                    duty, liability or obligation arising from or connected with
                    this Loan Agreement."

               (g)  Section 5.5, Section 5.6 and Section 5.7 are hereby added to
           the end of Article V of the Original Agreement to read as follows:

                         "Section 5.5. First Mortgage  Bonds.  The Company shall
                    execute  and  deliver to the  Trustee,  as  assignee  of the
                    Issuer,  its  First  Mortgage  Bonds.  The form of the First
                    Mortgage  Bonds  will be  substantially  as set forth in the
                    Company's  Supplemental  Indenture to its Mortgage  executed
                    and delivered to the Trustee on the  effective  date of this
                    First Amendment."

                         "Section 5.6. Payment of the Bonds from Payments of the
                    First  Mortgage   Bonds  and  Other  Amounts.   Payments  of
                    principal  of, and  premium,  if any,  and  interest on, the
                    First  Mortgage  Bonds by the  Company  to the  Trustee,  as
                    assignee of the Issuer,  shall  constitute  payments of such
                    amounts on the loan under Section 5.1(a). The Bonds shall be
                    payable from  payments made by the Company to the Trustee of
                    principal and interest on the First Mortgage Bonds delivered
                    hereunder.  Payments of principal of or premium,  if any, or
                    interest on, the Bonds with moneys held under the  Indenture
                    for such payment  shall be deemed to be like  payments  with
                    respect to the First Mortgage Bonds.  The obligations of the
                    Company  to make  payments  under the First  Mortgage  Bonds
                    shall be absolute and unconditional.  Whenever the Bonds are
                    redeemable  in whole or in part,  the Issuer will redeem the
                    same  upon  the  request  of the  Company,  and the  Company
                    covenants   and  agrees  to  pay  an  amount  equal  to  the
                    applicable  redemption price of the Bonds as a prepayment of
                    principal of and interest due on the First  Mortgage  Bonds.
                    If  the  Company  prepays  the  First  Mortgage  Bonds,  the
                    Company's  obligations  under  Section 5.1 will be satisfied
                    and there will be a  corresponding  redemption of the Bonds.
                    Whenever  payment  or  provision  therefor  has been made in
                    respect  of  the  principal  of or  interest  on  all or any
                    portion  of the  Bonds  in  accordance  with  the  Indenture
                    (whether at maturity or upon  redemption  or  acceleration),
                    the First  Mortgage Bonds shall be deemed paid to the extent
                    such  payment  or  provision  therefor  has been made and is
                    considered  to be a payment of  principal or interest on the
                    Bonds.  If the  Bonds or any  portion  thereof  are  thereby
                    deemed  paid in full,  First  Mortgage  Bonds in a principal
                    amount equal to the principal  amount of the Bonds so deemed
                    to be paid shall be  cancelled  and returned to the Company.
                    Subject to the  foregoing  or unless the Company is entitled
                    to a credit under this Loan Agreement or the

                                      -4-

<PAGE>

                    Indenture, all payments shall be in the full amount required
                    under the First Mortgage Bonds.

                         The  Issuer,  by  the  terms  of the  Indenture,  shall
                    require  the  Trustee  to notify  in  writing  the  Mortgage
                    Trustee of all payments or credits with respect to the First
                    Mortgage Bonds.

                         All First  Mortgage  Bonds  shall  equally  and ratably
                    secure all outstanding Bonds."

                         "Section 5.7.  Assignment  of Issuer's  Rights to First
                    Mortgage  Bonds.  As security  for the payment of its Bonds,
                    the Issuer  hereby  pledges  and  assigns to the Trustee the
                    First  Mortgage  Bonds  and the  right to  receive  payments
                    thereunder.  The Issuer directs the Company, and the Company
                    agrees,  to pay to the  Trustee at its  principal  corporate
                    trust office all payments on the First Mortgage  Bonds,  and
                    other payments due and payable to the Trustee hereunder. The
                    Company will make payments  directly to the Trustee  without
                    defense  or  set-off by reason of any  dispute  between  the
                    Company  and the Trustee or the  Issuer.  The Issuer  hereby
                    agrees that the Trustee as assignee  may enforce any and all
                    rights and remedies hereunder, but retains the right to also
                    proceed  in  its  own  name  against  the  Company  for  the
                    enforcement of the specific performance of any obligation of
                    the Company under Sections 5.2, 7.2 and 9.3; provided,  that
                    in any such action seeking specific performance,  the Issuer
                    shall  have no rights  with  respect  to the First  Mortgage
                    Bonds and in such  event the  obligation  of the  Company to
                    make the payments  required to repay the loan  hereunder and
                    the purchase price for the Bonds and payments required under
                    the First  Mortgage  Bonds  shall  remain  unconditional  as
                    provided in Section 5.4.

                         The Issuer and the Company  covenant and agree that the
                    First  Mortgage  Bonds  will at all  times  be (i) in  fully
                    registered   (both   principal  and  interest)   form;  (ii)
                    registered    in   the   name   of   the   Trustee;    (iii)
                    non-transferable  except as  provided in the  Mortgage;  and
                    (iv)   appropriately   marked  to   indicate   clearly   the
                    restrictions  on the transfer  thereof  imposed by this Loan
                    Agreement."

     Section  2.03.  Amendments  to Article VI of the  Original  Agreement.  (a)
Section 6.1 of the Original Agreement is hereby amended to read as follows:

                         "Section 6.1.  Maintenance  of  Existence.  The Company
                    agrees  that during the term of this Loan  Agreement  and so
                    long  as any  Bond is  outstanding,  it  will  maintain  its
                    corporate  existence,  will continue to be a corporation  in
                    good standing under the laws

                                      -5-

<PAGE>

                    of the State,  will not dissolve or otherwise dispose of all
                    or substantially  all of its assets and will not consolidate
                    with or merge  into  another  legal  entity or permit one or
                    more  other   legal   entities   (other  than  one  or  more
                    subsidiaries  of the Company) to  consolidate  with or merge
                    into it, or sell or  otherwise  transfer  to  another  legal
                    entity all or  substantially  all its assets as an  entirety
                    and  dissolve,   unless  the  Company's   actions  shall  be
                    permitted under the terms of the Insurance Agreement and (a)
                    in the case of any merger or  consolidation,  the Company is
                    the  surviving   corporation,   or  (b)(i)  the   surviving,
                    resulting  or  transferee  legal  entity  is  organized  and
                    existing  under  the  laws  of the  United  States,  a state
                    thereof  or the  District  of  Columbia,  and  (if  not  the
                    Company)  assumes  in  writing  all the  obligations  of the
                    Company  under this Loan  Agreement,  the  Mortgage  and the
                    First Mortgage Bonds and (ii) no event which constitutes, or
                    which with the giving of notice or the lapse of time or both
                    would constitute an Event of Default shall have occurred and
                    be continuing  immediately after such merger,  consolidation
                    or transfer."

          (b)  The last  sentence of Section 6.2 of the  Original  Agreement  is
hereby amended to read as follows:

                         "A  copy of each  such  report,  as well as each of its
                    quarterly  reports to  shareholders,  will be filed with the
                    Issuer and the Bond Insurer."

          (c)  The second paragraph of Section 6.5 of the Original  Agreement is
hereby amended to read as follows:

                         "The Company  covenants  and agrees to notify  promptly
                    the  Trustee,  the  Issuer  and  the  Bond  Insurer  of  the
                    occurrence  of any event of which the Company has notice and
                    which event would  require the Company to prepay the amounts
                    due hereunder  because of a redemption  upon a determination
                    of taxability."

          (d)  Section 6.7 of the Original Agreement is hereby deleted.

          (e)  Section 6.8 is hereby added to the Original  Agreement to read as
follows:

                         "Section  6.8.  Purchase of Bonds by the  Company.  The
                    Company  shall  not  purchase  or  otherwise  acquire  Bonds
                    without the prior written consent of the Bond Insurer unless
                    the Company  redeems or cancels such Bonds on the day of any
                    such purchase."


                                      -6-

<PAGE>

                                                        -9-


     Section  2.04.   Amendment  to  Section 8.1  of  the  Original   Agreement.
Section 8.1 of the Original Agreement is hereby amended to read as follows:

                    "The  Company  may assign its rights and  obligations  under
                    this Loan  Agreement  with the prior written  consent of the
                    Issuer and the Bond Insurer,  but no assignment will relieve
                    the Company from primary liability for any obligations under
                    this Loan Agreement."

     Section 2.05. Amendments to Article IX of the Original Agreement.  (a)  The
first  paragraph of  Section 9.1 of the Original  Agreement is hereby amended to
read as follows:

                         "Whenever  any Event of Default under the Indenture has
                    occurred  and is  continuing,  the  Trustee  may,  with  the
                    consent of the Bond Insurer and shall, upon direction of the
                    Bond Insurer,  take whatever action may appear  necessary or
                    desirable to collect the payments then due and to become due
                    or to enforce performance of any agreement of the Company in
                    this Loan Agreement or in the First Mortgage Bonds."

          (b)  The last paragraph of  Section 9.1  of the Original  Agreement is
hereby amended to read as follows:

                         "Except  as  may   otherwise  be  provided   under  the
                    Mortgage,  nothing in this Loan Agreement shall be construed
                    to permit the Issuer,  the Trustee,  any  Bondholder  or any
                    receiver in any  proceeding  brought  under the Indenture to
                    take possession of or exclude the Company from possession of
                    the  Project  by  reason  of the  occurrence  of an Event of
                    Default."

          (c)  Section 9.2 of the Original  Agreement is hereby  amended to read
as follows:

                         "Section 9.2.  Delay Not Waiver;  Remedies.  A delay or
                    omission by the Issuer,  the Bond  Insurer or the Trustee in
                    exercising  any  right or remedy  accruing  upon an Event of
                    Default shall not impair the right or remedy or constitute a
                    waiver of or acquiescence in the Event of Default. No remedy
                    is exclusive of any other remedy. All available remedies are
                    cumulative."

     Section 2.06.   Amendments   to  Article  X  of  the  Original   Agreement.
(a) Section 10.4 of the Original Agreement is hereby amended to read as follows:

                         "After the issuance of the Bonds,  this Loan  Agreement
                    may not be  effectively  amended or  terminated  without the
                    written  consent of the  Trustee,  the Bond  Insurer and the
                    Tender Agent and in  accordance  with the  provisions of the
                    Indenture."

                                      -7-

<PAGE>

          (b)  Section  10.10 is  hereby  added to the end of  Article X  of the
Original Agreement to read as follows:

                         "Section 10.10.   Third  Party  Beneficiary.  The  Bond
                    Insurer  is  a  third   party   beneficiary   of  this  Loan
                    Agreement."


                                   Article III

                                  Miscellaneous

     Section  3.01.  Agreement  Confirmed.  Except  as  amended  by  this  First
Amendment,  all of the provisions of the Original Agreement shall remain in full
force and effect,  and from and after the effective date of this First Amendment
shall be deemed to have been amended as herein set forth.

     Section 3.02. Severability.  If any provision of this First Amendment shall
be held or deemed to be or shall,  in fact, be inoperative or  unenforceable  as
applied in any particular case in any  jurisdiction or  jurisdictions  or in all
jurisdictions,  or in all cases because it conflicts with any other provision or
provisions  hereof or any  constitution or statute or rule of public policy,  or
for any other reason,  such circumstances shall not have the effect of rendering
the  provision in question  inoperative  or  unenforceable  in any other case or
circumstance, or of rendering any other provision or provisions herein contained
invalid, inoperative, or unenforceable to any extent whatever.

     Section 3.03.  Counterparts.  This First  Amendment  may be  simultaneously
executed in several counterparts,  each of which shall be an original and all of
which shall constitute but one and the same instrument.

     Section 3.04.  Applicable  Provisions of Law. This First Amendment shall be
governed by and construed in accordance with the laws of the State of Missouri.

     Section 3.05.  Effective Date. This First Amendment shall become  effective
on the date the Trustee has received the consent of the Trustee to the execution
hereof.

                                      -8-

<PAGE>



     In Witness  Whereof,  the Issuer and the  Company  have  caused  this First
Amendment to be executed in their respective corporate names, and the Issuer has
caused its seal to be  hereunto  affixed  and  attested  by its duly  authorized
officer, all as of the date first above written.

                                          State Environmental Improvement and
                                            Energy Resources Authority



                                          By: /s/ Charles D. Banks
                                             -----------------------------------
                                                         Chairman

[Seal]

Attest:


By: /s/ Deron L. Cherry
   ----------------------------------
               Secretary

                                          Union Electric Company, dba AmerenUE



                                          By: /s/ Jerre E. Birdsong
                                             -----------------------------------
                                            Title:  Vice President and Treasurer


                                      -9-

<PAGE>

                             Consent of the Trustee

     Pursuant  to  Section 10.4   of  the  Loan  Agreement   between  the  State
Environmental  Improvement  and  Energy  Resources  Authority  of the  State  of
Missouri (the "Issuer") and Union Electric Company dba AmerenUE (the "Company"),
dated as of December 1,  1992, UMB Bank & Trust, N.A., successor to State Street
Bank and Trust  Company of Missouri,  N.A., as Trustee,  hereby  consents to the
execution  and  delivery of the First  Amendment to Loan  Agreement  dated as of
February 1, 2004 between the Issuer and the Company.

                                        UUMB Bank & Trust, N.A., successor to
                                          State Street Bank and Trust Company of
                                          Missouri, N.A.



                                        By: /s/ R. A. Dengler
                                           -------------------------------------
                                           Its  Authorized Officer

Date:  March 26, 2004