Journalartikel

Jahr der Veröffentlichung: 1999

Seiten: 1067-1079

Zeitschrift: Journal of Experimental Biology

Bandnummer: 202

Heftnummer: 9

ISSN: 0022-0949

eISSN: 1477-9145

Verlag: The Company of Biologists

Abstract: 
Pharmacological examinations of isolated auricles from Sepia officinalis were carried out to analyze the putative role of the monoaminergic transmitter/receptor system in the control of auricle function. In conjunction with histofluorescence studies and HPLC analyses, evidence of a double excitatory serotonergic and noradrenergic innervation of the auricles was obtained. Serotonin-induced positive chronotropic and inotropic effects were blocked by mianserin (5-HT1 and 5-HT2) but not by cyproheptadine (5-HT2), It is assumed that the auricular serotonin (5-HT) receptor represents a 5-HT1-like subtype and is not identical to the ventricular 5-HT receptor. Noradrenaline, adrenaline and dopamine evoked mainly positive chronotropic reactions and less prominent positive inotropic reactions. The potency range (pD(2) frequency: noradrenaline 6.65 much greater than adrenaline 5.69 > dopamine 5.34; pot amplitude: noradrenaline 6.09 greater than or equal to adrenaline 5.91 > dopamine 5.33) indicates out that noradrenaline might be the effective neurotransmitter in vivo. The alpha-mimetics clonidine (alpha(2)) and phenylephrine (alpha(1)) induced positive chronotropic and inotropic effects, while the beta-mimetics albuterol (beta(2)>beta(1)) and dobutamine (beta(1)) revealed only positive inotropic reactions. The beta-agonist isoprenaline mimicked the positive chronotropic effects of noradrenaline and induced the strongest positive inotropic effects of all the agonists tested. Urapidil (alpha(1)) or phentolamine (alpha(1) and alpha(2)) blocked only the positive chronotropic effects of noradrenaline and isoprenaline, The positive inotropic effects of isoprenaline could be blocked by the adenylate cyclase inhibitors MDL-12,330A or SQ-22,536, which had no effect on the chronotropic effects of isoprenaline. These results suggest that two catecholaminergic receptors are present in the auricles of Sepia officinalis: an alpha-like adrenoreceptor mediating mainly chronotropic effects, and a beta-like receptor which appears to mediate inotropic effects by activating the cyclic AMP pathway. These results suggest that the auricles exert a regulatory effect on ventricular performance.

Harvard-Zitierstil: Versen, B., Gokorsch, S., Fiedler, A. and Schipp, R. (1999) Monoamines and the isolated auricle of Sepia officinalis:: Are there β-like receptors in the heart of a cephalopod?, Journal of Experimental Biology, 202(9), pp. 1067-1079

APA-Zitierstil: Versen, B., Gokorsch, S., Fiedler, A., & Schipp, R. (1999). Monoamines and the isolated auricle of Sepia officinalis:: Are there β-like receptors in the heart of a cephalopod?. Journal of Experimental Biology. 202(9), 1067-1079.