Guinea pig brain membranes

Ki of 9 nM in guinea-pig brain membranes [79]. The compound was also reported to have an ED50 of 2.2 mg/kg in a CNS hypertension model. 

Tam, S.W., and Cook, L. Sigma opiates and certain antipsychotic drugs mutually inhibit (+)3H-SKF-10,047 and 3H-haloperidol binding in guinea-pig brain membranes. Proc Natl Acad Sci USA 81 5618-5621, 1984. 

Displacement of [3H]DADLE from guinea pig brain membrane binding sites. 

When the efficacy of biphalin-stimulated G protein activation was examined (Table 3) in delta opioid receptor-transfected CHO cells, an efficacy ratio of 0.42 was determined as compared with deltorphin-II and DPDPE, the latter a reference delta-selective agonist. Such low efficacy values suggest that biphalin does not efficiently stimulate the G protein through the delta receptor [9]. Relative affinities of biphalin and morphine for mu, delta, and kappa binding sites in guinea pig brain membranes are shown in Table 4. 

Table 3.8. BINDING AFFINITIES (K IN nM) AND SELECTIVITIES OF NOR-BNI AND BNI IN COMPETITION WITH [3H]DAMGO (ft), [3H]DADLE (S) AND [3H]EK ((c) USING GUINEA-PIG BRAIN MEMBRANES [132]...

Table 1 The 8, p, and k opioid receptor binding profile using selected pyridomorphinans in rat or guinea pig brain membranes...

Guinea pig brain membranes were prepared as above incubated in 50 mM Tris-HCl, pH 7.4, containing 1 p-g/ml captopril and PIC. Nonspecific binding was determined using 1 p,M U69,593. 

Rat brain membranes were used in p- and 8-receptor binding assays and guinea pig brain membranes were used in the K-receptor binding assay K, inhibition constant... 

Lau W-M, Freeman SE and Szilagyf M (1988). Binding of some organophosphorus compounds at adenosine receptors in guinea pig brain membranes. Neurosci Lett, 94, 125-130. 

A" inhibition values ji, 8 and k opioid binding to guinea pig brain membranes by kappa opioids... 

All compounds were examined for their affinity and selectivity at p, 8 and k opioid receptors in Guinea Pig brain membranes labeled with [ HjDAMGO (p), [ HlNaltrindole (8) and [ H]U69,593 (k) (Table 1). The antinociceptive activity of the two morphinans with the highest affinity and selectivity were examined further in the tail flick and acetic-acid writhing tests in mice. 

Furthermore, the substitution of methyl groups at the T and 6 position of Tyr (Dmt) yielded Dmt-Tic- peptides (3) endowed with dramatically increased 8-affinity, comparable to the 8-affinity observed with deltorphins [59-63]. On the other hand, p-affinity of 3 rose 20-fold relative to 1 and 2, while k-affinity increased over 40-fold in guinea pig brain membranes, 20-fold in rat brain synaptosomes compared to 2 and approximately 40-fold for both membrane preparation relative to 1. Inclusion of the Tyr-D-Ala-Phe message domain (4) essentially eliminated opioid interaction with k-receptors, whereas 8- and p-affinities were only moderately altered in comparison to DYN (1-11) -NH2 (Table... 

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