Involvement of central and peripheral histamine H3 receptors in the control of the vascular tone and oxygen uptake in the mesenteric circulation of the rat

• Autorzy: Obuchowicz R. , Pawlik M.W. , Brzozowski T. , Konturek S.J. , Pawlik W.W.
• Języki publikacji: EN

Abstrakty

EN

Data concerning cardiovascular effects of peripherally and centrally located histamine H3 receptor stimulation are contradictory, and despite excessive studies their role in the control of the cardiovascular function have not been cleared yet. Effect of histamine H3 receptors activation have been attributed to modulation of sympathetic system activity but exact role of peripherally and centrally located histamine H3 receptors stimulation in the modulation of vascular tone of the mesentery and intestinal metabolism remains unexplored. Aim of the present study was to evaluate the role of centrally and peripherally located histamine H3 receptors in the modulation of vascular tone of the mesentery and metabolic activity of intestinal tissue. In anesthetized rats total mesenteric blood flow (MBF), mucosal intestinal blood flow (LDBF), intestinal oxygen uptake (VO2) and arterial pressure (AP) were determined. Intestinal arterial conductance (C) was also calculated. Administration of the selective histamine H3 receptor agonist imetit (10 µmol/kg i.a) evoked marked changes in hemodynamic and metabolic parameters; MBF, LDBF, C and VO2 were significantly increased, whereas AP was significantly decreased. Pretreatment with histamine H3 receptor antagonist clobenpropit (4 µmol/kg i.a.) abolished imetit-induced circulatory and oxygen uptake responses. Clobenpropit (4 µmol/kg i.a.) alone failed to affect the MBF, LDBF, AP, C and VO2 values. Central administration of imetit (0.1 µmol i.c.v.) markedly increased AP and decreased MBF, LDBF, C and VO2. Pretreatment with histamine H3 receptor antagonist clobenpropit (0,4 µmol i.c.v.) diminished circulatory and metabolic responses to centrally injected imetit. Central histamine H3 receptors blockade by clobenpropit evoked no significant changes in the mesenteric arterial and mucosal microcirculatory blood flow, intestinal metabolism and mean arterial pressure. We conclude that, peripheral histamine H3 receptors when stimulated decreases vasoconstrictory tone of the mesenteric artery and precapillary structures and evokes increase of intestinal oxygen uptake. This might be in part due to inhibition of sympathetic postganglionic fibers vasopressor activity. Central histamine H3 receptor stimulation activates vasoconstrictory sympathetic adrenergic system with possible involvement of other, presumably non-histaminergic receptors system. At basal conditions neither central nor peripheral histamine H3 receptors are involved in the control of mesenteric macro - and microcirculation and intestinal oxygen consumption.

Słowa kluczowe

EN

histamine H3; receptor; mesenteric circulation; cardiovascular effect; rat; oxygen uptake; vascular tone

• Wydawca: -
• Czasopismo: Journal of Physiology and Pharmacology
• Rocznik: 2004
• Tom: 55
• Numer: 1,2
• Opis fizyczny: p.255-267,fig.,ref.

Twórcy

autor

Obuchowicz R.

• Jagiellonian University Medical College, Grzegorzecka 16, 31-531 Krakow, Poland

autor

Pawlik M.W.

autor

Brzozowski T.

autor

Konturek S.J.

autor

Pawlik W.W.