INCREASE OF TNFaCONCENTRATlON IN SERUM AND LIVER BUT NOT IN MYOCARDIUM DURING PACING-INDUCED HEART FAILURE Stephanie Aker, Till Neumann, Ine Konietzka, Serge] Belosjorow, Gerd Heusch, Ralner Schulz Dept. of Pathophyslology, University of Essen, Germany

In heart failure (HF) patisnts with left ventricular (Lv) systolic dysfunction, sarum TNFa-concentration (sTNFa) is Incmaaad. An increase In myocardial TNFa-concentration (mTNFa) ting intracoronary TNFa-infuabn is arsodated with the development of contract&z dyahmtion In dogs. To study whether the increase in sTNFa is a cause or conaequartce of HF, HF was Induced by LV padng (400 bpm) h 10 chronIcally inatrumantad mbbita over 3 weeks. Ednxar~aphy raveded an hrasased LV and-dtaatolic diameter and a reduced shortening fra&n. 9 sham- operated rabbits served as controls. sTNFa. mTNFa and liver TNFa-concenlration (ITNFa) (WEHI-ceU aaaay) were measured. aTNFa was increased In HF rabbits compared to controls (267k27 vs. 171*24 U/ml, MeaniSEM, ~4.05). Also lTNFa was increased In HF compared to controls (221M95 vs. 149hl25 U/g, p<O.O5). In contrast, mTNFa did not differ between HF and controls (14&l 1 va.1251t14 U/ml, NS). In the liver (HE-statnlng), the number of leukocytes was higher In HF than in controls (11240 vs. 48*14 &mm?, peO.05). Close, linear correlations between the number of leukocytes and RNFa (r-0.78) as wel as between ITNFa and sTNFa (r=O.68) were demonstrated. In this HF model, mTNFa remains unchanged. The inaease in sTNFa appeara to be a consequance rather than a cause of HF, and it is posaibiy a result of gasbolntestinal congestton and subclinical Inflammation.

(;RADI:AL LOSS OF CORRELATION BETWEEN BLOOD FLOW AND OXYGEN CONSUMPTION IN THE ISCHAEMIC PORCINE LEFT VENTRICLE David J.C. Alders, Johan Groeneveld & Hans van Beck. Laboratory for Physiology, VU University Medical Center. Amsterdam. the Setherlands

lleterogeneit) ofm~ocardial blood flow 15 well-known. RecentI! is has become possible to meawre blood flow and oxygen consumption in the same tissue sample. using the radioactlve microsphere method and “C nuclear magnct~i resonance spectroscop>. rcspcctlvely. These parameters arc correlated in the control situation. hut II is not known If this correlation is lost during ischaernla ofthe left \cntricIc. Pigs (n = 6) were sedated, intubated. and anaesthctized I’hc thorax was opened and the heart exposed. A small occludcr

\\as placed around the left anterior dcwznding (I AD) coronae arter). A timed double lahellng protocol ulth ( acetate, infused directly into the LAD. sas appl~cd. Rlo~~l tlov. was measured before and after 30 minute\ ot partial coronary occlusion. Pan of the leti ventricle \\as quickl! freeze-clamped and cut into small pieces (35-200 mg dp

height) I..AD pressure was reduced to a mean of35 mm[lg (mean arterial prcswre 89 mmHg). resulting III a mean blood flo\r reduction of 5 I% In samples in \\hlch Mood flw r\as reduced less than ?5%, correlation of hlood flow and ox>gcn

consumption wab already decreased (R‘ !, 28) When hlootl flo\v was reduced to a greater extent. this relation was completely lost. We conclude that moderate coronary constriction leads to a gradual IOV+ of correlation hetwcn oxygen dclt\en and oxygen con\umptllln

P 38 MAPK AND APOPTOSiS IN PACING- NDUCED HEART FAILURE IN RABBITS

Stephanie Aker, Ralner Schulz, Ine Koniettka, Sergej Belosjorow, Gerd Heusch. Dept. of Pathophyslology, University of Essen, Germany

In human chronically ischemic. failing myocardium. the phosphorylatlon of ~38 MAPK is increased. In experimental studies of lschemialreperfusion, Increased ~38 MAPK phosphorylation (p38 MAPK-p) is associated with increased myocyte apoptosis. We tested whether or not ~38 MAPK is also activated In pacing-induced heart failure (HF) In rabbits, which is not associated wtth signtflcant myocardlal ischemia. In 6 chronlcelly Instrumented rabtslts, HF wes Induced by left ventricular (LV) pacing (400 bpm) over 3 weeks. Echocardiography revealed an increase in LV end- dlastollc diameter from 15i2 to 18ti mm and a reduction in shortening fmdion from 35rtS to 11*4% (Mean&EM, both ~0.05). Total p38 MAPK did not differ between HF and 6 sham-operated rabbits. ~38 MAPK-p was increased in HF compared to sham (766 vs. 42*10% of total p38 MAPK, ~0.05). The number of TUNEL-positive cardiomyocyles was also Increased In HF compared to sham (0.022&0.007 vs. 0.003~.002%, p<O.OS). Overall, p38 MAPK-p correlated to the extent of apoptosis (n=12, r-0.60). In thii HF model, p38 MAPK-p and apoptosis are increased. Further studies will have to deftne whether or not chronic blockade of p38 MAPK adivity can interfere with apoptosls and thereby attenuate the progression of HF.

NEUROPEPTIDE Y Y, RECEPTOR FtiNCTIONAL RFSPONSlVENESS IS ENHANCBD DURING ESTABLISHED CARDIOMYOCYTE RY?ERTRO?fiY Adrian Allen, David Bell. EUzabaA K&o, & Barbara McDemon Centre for Cardiovascular and Genaics R-h, (&&n’s University Belfast. U K.

We have prewously shown that NPY, acting at YI receptors, produces a positive conoactile response in normal ventricular myocytea. In the spontaneously hypcrtcnsive ra1 (SHR), cardiomyocyte hypertrophy ia evident at I(i-2Owks of age. The aim of thla study was to invcahgate whether (i) the exprcsaion of the ventricular cell NPY Y, receptor is altered in catabliahed hvoertroahv. and (ii) the functional rcauonsivencss of the NF’Y YI ,r-~- r-~,. ~ I

receptor is altered, usin NPY and the. Y, receptor selective agonist and antanoniat. and BfBP3226, respecave~y, in ‘v&i&r &diomyocytes iso&d from SHR and me-matched normotenaive control Wintar Kyoto (WKYI rat.8 (12- 2?iwks). M’Y Y, rcccptor mRNA, ass& by RT-PCR, waa attenuated f53+26 v. 204+85%. PcO.05) in SHR at 2Owks compared to age-matched WKY conuol &.The potency of NPY and LPNPY to stimulate the Y, receptor-mcdi8!ed positive contractile amplitude (video edge detect&), in the presence of elevated Ca” (3mhi), was unaltered in WKY rat cardiomyocytcs with the progression of age. However, in SHRz at 2Chvk.9, the pokncica of NPY and LPNPY 10 elicit positive effects on myocyte contractile amplitude were greatly enhanced (NPY: 4.8xlO~“M; I.PNTJY: 5.9x10-W) Wnparcd to WKY cells (NPY: l.Sxlo”4vl; LPNPY: 2.3xlO~‘k). The Y, receptor-selective antagouiat, BIBP3226 (i) aboliabed the positive contractile effects of both peptidea in 12-2Owk myocytcs l?om both strains, and (ii) in the oreaence of NPY. unmasked the o~~osina negative contractile ‘function of NPY i’, receptors. A r&ctio~ in the expmaion of NPY Y, receptors and an enhanced Cal’-dependent NPY Y, receptor-media&l functional response during catahliahcd cardiomycqte. hypcruophy would indicate increaacd sensitivity of WY Y, receptor activity coupled to a post receptor mcchaniam of actIon.