The Presence of a Substance with Sympathin E Properties in Spleen Extracts

Abstract

Extracts of fresh cattle spleen possess a pressor activity equivalent to some 10 μg adrenaline per g of tissue. The purified substance increases the heart rate and raises the blood pressure of the cat in chloralose anaesthesia. The pressor action is enhanced by cocaine. Ergotamine in doses which annul or reverse the pressor action of adrenaline is less active in depressing the action of purified spleen extracts, which in this respect resembles certain catechol amino-bases, such as nor-adrenaline or 3: 4-dihydroxy-nor-ephedrine (D. N. E.). Adrenaline inhibits the isolated rabbit's intestine and the non-pregnant cat's uterus more powerfully than equipressor doses of spleen extracts or D. N. E. Purified spleen extracts, like D. N. E., are less active in stimulating the rabbit's uterus than equipressor doses of adrenaline. Purified spleen extracts and D. N. E. have a weaker pupil dilating action than equipressor doses of adrenaline. Purified spleen extracts stimulate the isolated heart in much the same way as equipressor doses of adrenaline and D. N. E. Purified spleen extracts and D. N. E. do not give the fluorescence reaction characteristic of adrenaline in equipressor concentrations. Purified spleen extracts and D. N. E. give the FeCl3 colour reaction to about the same strength as equipressor concentrations of adrenaline. The biological tests, colour and fluorescence reactions of purified spleen extracts thus bear a good resemblance to those of nor-adrenaline or D. N. E. and differ from those of adrenaline. The similarity between the action of the purified spleen extracts and the postulated sympathin E on the one hand and nor-adrenaline or D. N. E. on the other is pointed out.