| Abstract: | Since superior protection against differentgastrointestinal and liver lesions and antiinflammatoryand analgesic activities were noted for pentadecapeptideBPC (an essential fragment of an organoprotective gastric juice protein named BPC), thebeneficial mechanism of BPC 157 and its likelyinteractions with other systems were studied. Hence itsbeneficial effects would be abolished by adrenal glandmedullectomy, the influence of different agents affecting ,  , and dopamine receptors on BPC 157gastroprotection in 48 h restraint stress was furtherinvestigated. Animals were pretreated (1 hr beforestress) with saline (controls) or BPC 157 (dissolved insaline) (10  g or 10 ng/kg body wt intraperitoneallyor intragastrically) applied either alone to establishbasal conditions or, when manipulating the adrenergic or dopaminergic system, a simultaneousadministration was carried out with various agents withspecific effects on adrenergic or dopaminergic receptorsgiven in milligrams per kilogram intraperitoneally except for atenolol, which was givensubcutaneously] phentolamine (10.0), prazosin (0.5),yohimbine (5.0), clonidine (0.1) (-adrenergicdomain), propranolol (1.0), atenolol (20.0)(-adrenergic domain), domperidone (5.0), and haloperidol(5.0) (peripheral/central dopamine system).Alternatively, agents stimulating adrenergic ordopaminergic systemsadrenaline (5.0) or bromocriptine(10.0)-were applied. A strong protection, noted followingintragastric or intraperitoneal administration of BPC157, was fully abolished by coadministration ofphentolamine, clonidine, and haloperidol, andconsistently not affected by prazosin, yohimbine, ordomperidone. Atenolol abolished only intraperitoneal BPC157 protection, whereas propranolol affectedspecifically intragastric BPC 157 protection.Interestingly, the severe course of lesion developmentobtained in basal conditions, unlike BPC 157gastroprotection, was not influenced by the applicationof these agents. In other experiments, when adrenalineand bromocriptine were given simultaneously, a strong reductionof lesion development was noted. However, when appliedseparately, only adrenaline, not bromocriptine, has aprotective effect. Thus, a complex protectiveinteraction with both -adrenergic (e.g.,catecholamine release) and dopaminergic (central)systems could be suggested for both intragastric andintraperitoneal BPC 157 administration. The involvementof -receptor stimulation in BPC 157 gastroprotection appearsto be related to the route of BPC 157 administration.The demonstration that a combined stimulation ofadrenergic and dopaminergic systems by simultaneous prophylactic application of adrenaline(- and -receptor stimulant) andbromocriptine (dopamine receptor agonist) maysignificantly reduce restraint stress lesionsdevelopment provides insight for further research on the beneficial mechanism ofBPC 157. |
