Thioperamide, a histamine H3-receptor blocker ...

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1023-3830/98/030109-06 $ 1.50+0.20/) linflammation Research. Thioperamide, a histamine Hz-receptor blocker, facilitates vasopressor response to footshocks.
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Thioperamide, a histamine H3-receptor blocker, facilitates vasopressor response to footshocks Y. Acuñar, Y. N,Iathison:, H. A. Canrpos2 and A. lsraell-l rSchool

of Ph¡nnacy. Uni\ellsidilcl Centr¡l c1(- Vcnezuela. Cu¡ilcls- VcnezLrel¡ María Vat-9as School ol_ Vlcdicine. l-jniver\iLllLLl aerltrrl Lie Vene,,uel¿r. Crracr\- Vcncrucl¡ rAp.utarkr Post.rl 50176. Srbrna Granclc 1050A. Crrirca\. VcncrLrcla- F¡x +58 I t)79 0015 2Jose

Reccilcd l8 August 1997i returned f¡r revision l-l Ocrcber l99li ¡crepte(l bl E. Neugebaucr I Dcccnrlrer l99l

Abstract. Objttlit,c untl Desígn. Wc ¡ssessccl thc funclion¿Ll l',lc nl rltL hi.rrl ir¡ H tr(cplot i.l con.ciour lrrrcl .,'1.

ol the sympxtho¿d|en¿l lxis. Spr.ague Dawley lats. wilh or wilhoLrl ce¡ebr-ovenllicular cannul¡. wcr-c subjcctccl to milcl firotclu.ing actiVatior'l

Materid: M e

lntroduction

Thc pe|ipheral fulctir¡ral rolc ol hislarninc (llA)

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detelmined using a tail-cull plethysmoglaph. Tredf tenfs: Saline, phentol¡nilte (3 ntg/k-r. i.p.). (R) ¡lpha lluo|onethylhistidine (AFMH) (I00 mg/kg. i.p.. or I(X)¡r-e/ 5 pL, i.v.t.). (lt) alphamcthylhistam ine (AN4H1 (2 nrg/kg. i.p. or 1(X)¡rg/5pl, i.v.t.). ¡hioperamidc (TH[O) (i or'2mg/lig. i.p.. or' 1(X)pg/5p1. i.v.t.), mepyraminc (l0mg/kg. i.p.), cimetidire (2 mg/kg. i.p. ).

¡1larnnals ancl its intcrircti0n with the s\nlllathetic svstenl h¡s bccn r-ecentlv sustainecl. Our findings shou,thrt depletion ol hist¡rrine levels afier in-eversible inhibition ol histaurinc biosynthesis wilh a lirLororncthylhistidinc (AFMHl incluces an incrcasc in ovcr¡ll syn¡pathetic ¡ctivity ancl cluses hypcrlcnsion 4nd tach¡,cardiii lll. A pcliphcral neuronal pool of hist¿irnire seems to bc involved in this interaction l2l since lnast cell hist¡lnine is poorly lfk:ctccl b¡, histidinc dccarboxy lasc inhibition j3l. The enhancenrent ol \ympathctic ¡ctivity by inhibition of histaminc bios)nthesis rv¡s shown inasuruclt

Methrxls;

lts the incrc¿isc in

shocks ¡rncl mean rrterial pressure (MAP) and hea¡t rate werc

Ulin.ty catecholilnrines were deter ined by lluorornetry. Slalistic¿l cliftt|cnccs betwccn cxpcrimcntal groulls wcle evlhrated b) Stl¡denl's I test or- one wayANOVA. Áerr//r. ljootshocks incrcasccl both MAP ur.l herrt r¿rtc. The

vas(4)l-cssor lesponse to foolshocks was lacilitated (p