| RESEARCH PAPER
|Year : 1994 | Volume
| Issue : 4 | Page : 270-276
Effects of chronic terbutaline and abana pretreatments on beta-adrenoceptor mediated relaxant responses of guinea-pig isolated trachea
P Bhattacharya, JD Bhatt, KG Hemavathi, OD Gulati
Effects of chronic pretreatment with Abana (a herbomineral formulation) on beta-adrenoceptor mediated guinea-pig isolated tracheal relaxation was studied. Chronic terbutaline (TER) pretreatment in the guinea-pig significantly reduced the contractile response of the isolated tracheal chain preparation to pilocarpine (PILO; 3.68 X lO-6) while the response to KCI (1.78 X 102M) was not modified. The maximal relaxant responses to isoprenaline (ISO), TER and aminophylline (AMINO) were significantly depressed in PILO-contracted isolated tracheal chain preparations but were not modified in KCI-contracted preparations. Chronic Abana pretreatment significantly depressed the contractile response to PlLO and significantly enhanced that to KCI. The maximal relaxations to the three relaxant drugs were not modified in PILO-contracted preparations while in KCI contracted preparations an increased sensitivity was observed. Chronic pretreatment with Abana plus TER caused marked depression of the contractile responses of the preparation to PILO; while KCI induced contractions were not modified. The maximal relaxations to the three relaxant drugs were markedly depressed in PILO-contracted preparations which were not significantly different from those in the chronic TER-pretreated group. In KCI-contracted preparations maximal relaxations by ISO, TER and AMINO were not modified. It is concluded that chronic Abana pretreatment in the guinea-pig does not affect either beta-adrenoceptor mediated tracheal relaxation or the decreased responsiveness of the tracheal smooth muscle induced by chronic TER pretreatment.
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