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Biomedical subjects

J E Shook

Publications and source records attributed to J E Shook.

47 records · Page 3Linked to original sources
PubMed1986

A novel bioassay for the NK-2 neurokinin receptor: the guinea pig gallbladder.

Although three neurokinin receptors (NK-1, NK-2, NK-3) have been identified by radioligand binding assays, only the NK-1 and NK-3 types have been found in smooth muscle bioassays. In this study, evidence is presented demonstrating functional NK-2 type receptors in the guinea pig gallbladder (GPGB). The potencies of the following neurokinins were determined in the GPGB and the guinea pig ileum (GPI): substance P (SP), physalaemin (PH), eledoisin (EL), substance K (SK) and kassinin (KA). ED50 values were determined by linear regression analysis of the dose-related increases in the force generated by each peptide. In the GPI, the rank order of potency was SP = PH = EL greater than SK = KA, indicating NK-1 selectivity. In the GPGB, the relative potencies were SK greater than KA greater than EL much greater than PH greater than SP, which is similar to that reported for the NK-2 receptor in radioligand binding assays. These findings demonstrate the NK-2 receptor tissue selectivity of the GPGB.

Animals↗
PubMed1986

Morphine dependence and diabetes. I. The development of morphine dependence in streptozotocin-diabetic rats and spontaneously diabetic C57BL/KsJ mice.

Spontaneously diabetic (db/db) and nondiabetic (db/m+, m+/m+) C57BL/KsJ mice were made dependent by a 9-day exposure to increasing doses of morphine-admixed food. Radioimmunoassay for morphine demonstrated that diabetic mice had significantly greater brain accumulations of morphine than nondiabetic littermates after morphine-admixed food. Despite their greater brain levels of morphine, diabetic mice showed significantly fewer behavioral signs of withdrawal after naloxone, and lost significantly less weight at 60 min after naloxone than their nondiabetic littermates. Streptozotocin-diabetic and nondiabetic rats rendered dependent by a 6-day i.p. infusion of morphine had equal brain levels of morphine, but the diabetic rats showed significantly fewer behavioral signs of withdrawal than nondiabetic rats at 24 and 48 hr after the end of the infusion. These results indicate that spontaneously diabetic mice and streptozotocin-diabetic rats were both significantly less physically dependent upon morphine than their respective nondiabetic controls and support our conclusion that the development of physical dependence upon morphine is reduced in experimental models of diabetes.

Animals↗
PubMed1986

Morphine dependence and diabetes. II. Alterations of normorphine potency in the guinea-pig ileum and mouse vas deferens and of ileal morphine dependence by changes in glucose concentration.

The effects of glucose in vitro at concentrations of 100, 200 and 400 mg/dl on responses of the guinea-pig ileum and mouse vas deferens to opiates were studied. Responses of the electrically stimulated ileum to normorphine were significantly reduced (IC50 values: 26.3 +/- 4.3, 40.5 +/- 3.7 and 71.8 +/- 16.6 nM) as the glucose concentration increased, whereas the potency of normorphine was not affected by equimolar substitutions of glucose with the nonmetabolizable sugar 3-O-methylglucose. The potency of naloxone to induce withdrawal contractions of ilea incubated in Ringer's solution for 3 or 4.5 hr with 1 microM morphine was also significantly decreased as the concentration of glucose in the incubations increased, indicating a reduction of acute dependence development by high glucose. The potency of normorphine was also reduced by increasing concentrations of glucose in electrically stimulated vasa deferentia from nondiabetic (db/m+, m+/m+) C57BL/KsJ mice (IC50 values: 0.53 +/- 0.01, 0.77 +/- 0.01 and 1.84 +/- 0.03 nM), but not in vasa deferentia from their diabetic (db/db) littermates. These results support our hypothesis that the decreased sensitivity to morphine and decreased development of physical dependence on morphine in in vivo models of diabetes reported previously by our laboratory is due primarily to the hyperglycemia associated with diabetes.

Animals↗
PubMed1984

The discriminative stimulus properties of the R2 isomer of viminol.

Viminol is a pyrrylethanolamine derivative which exists naturally as a racemic mixture containing six different stereoisomers. Viminol has been reported to exert both potent analgesic activity and minimal dependence liability. The analgesic component of racemic viminol has been attributed to the R2 isomer, while the antagonistic S2 isomer appears to be responsible for minimizing the dependence liability of the racemate. We tested the R2 isomer of viminol in rats trained to discriminate 3 mg/kg morphine sulfate from saline on a VI-15 sec schedule for sweetened milk reinforcement. The R2 isomer resulted in dose dependent morphine-like responding, with complete generalization to the 2.5 mg/kg dose of R2 viminol. The morphine-like discriminative stimulus properties of R2 viminol were reversed by naloxone in a dose-dependent fashion, with total blockade by 0.1 mg/kg naloxone. R2 viminol, like morphine, also had a biphasic effect on response rate with low doses increasing and high doses suppressing response rates. R2 viminol had a overall shorter time course than that reported for morphine, and its different physiological and behavioral effects may not occur simultaneously. These data suggest that R2 viminol exerts a subjective effect similar to that of morphine and supports the hypothesis that R2 viminol has opiate activity despite its lack of structural relationship to the opiate series.

Animals↗
PubMed1984

Characterization of the interaction of pentazocine and tripelennamine: drug discrimination and mu-receptor binding assay.

Abuse of the combination of pentazocine (P) and tripelennamine (T) reputedly produces an opiate-like euphoria not obtainable from either drug alone. To determine if this effect is related to interactions at the behavioral or receptor levels we tested this combination in rats trained to discriminate morphine from saline and in mu-receptor binding assays. Displacement of 3H-DHM was compared in morphine-naive, dependent and withdrawn states to determine the importance of prior morphine exposure. The morphine training cue (3 mg/kg) generalized to P but not to T. Combinations of T (0.3 and 1.0 mg/kg) with "no effect" doses of P (1 and 3 mg/kg) resulted in greater than additive increases in morphine-like responding. 3H-DHM was displaced by P but not T in naive, dependent and withdrawn states. Specific dose combinations of T (1 nM) with P (1 nM, 10 nM, 100 nM) resulted in enhanced displacement of 3H-DHM and was not related to prior morphine exposure. We conclude that the addition of T to P increases the mu-like subjective effects of P and this effect may be due to enhanced affinity of P for the mu-receptor.

Animals↗
PubMedDate not supplied

The effect of hallux abducto valgus surgery on the sesamoid apparatus position.

A new parameter, the tibial sesamoid-second metatarsal distance, was established to determine whether the sesamoids move in relation to the foot in hallux abducto valgus surgery. The reliability of the tibial sesamoid-second metatarsal distance was assessed and shown to be excellent. Seventy-five feet underwent surgical correction of hallux abducto valgus. Four radiographic parameters--the intermetatarsal angle, the hallux abductus angle, the tibial sesamoid position, and the tibial sesamoid-second metatarsal distance--were measured before and after surgery. The hallux abductus angle, intermetatarsal angle, and tibial sesamoid position were all significantly reduced following surgery. The tibial sesamoid-second metatarsal distance was not affected by hallux abducto valgus correction. Thus the correction in sesamoid position gained with hallux abducto valgus correction is a direct result of lateral translocation of the metatarsal head, with no contribution from change in position of the sesamoid apparatus relative to the foot.

Adolescent↗