The effect of the thirteen Dip-allatostatins on myogenic and induced contractions of the cockroach (Diploptera punctata) hindgut
1995
Lange, A.B. | Bendena, W.G. | Tobe, S.S.
The Dip-allatostatins are a group of 13 neuropeptides, ranging in size from 6 to 18 amino acids, identified from a cloned cDNA sequence of Diploptera punctata. All 13 Dip-allatostatins inhibited both myogenic and proctolin-induced contractions of the hindgut of D. punctata. Dip-allatostatins were capable of reducing a 5 X 10(-6) M proctolin-induced contraction in a dose-dependent manner, with ED50 values ranging from 1.7 X 10(-7) M for Dip-allatostatin 7 to greater than 1.3 X 10(-5) M for Dip-allatostatin 12. The effects of the Dip-allatostatins were reversible upon washing with saline. The free carboxylic acid (non-amidated) form of Dip-allatostatin 11, callatostatin 3 and callatostatin 5 showed a loss of inhibitory activity. In contrast to the inhibitory actions of the Dip-allatostatins on hindgut contractions, selected Dip-allatostatins (Dip-allatostatins 4, 6, 7, 10, 12), at concentrations ranging from 10(-7) M to 2 X 10(-5) M, did not alter the frequency or amplitude of myogenic contractions or inhibit proctolin-induced contractions of the cockroach oviduct muscle. Dip-allatostatins (Dip-allatostatins 1, 2, 4, 5, 6, 7) also had no effect on either myogenic or proctolin-induced contractions of the oviduct of Locusta migratoria.
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