Classical Conditioning of Insulin Effects in Healthy Humans

Classical Conditioning of Insulin Effects in Healthy Humans

Ursula Stockhorst, PhD, Eva Gritzmann, Kerstin Klopp, Yolanda Schottenfeld-Naor, MD, Achim Hübinger, MD, Hans-Walter Berresheim, Cert. Eng., Hans-Joachim Steingrüber, PhD and Friedrich Arnold Gries, MD

From the Institute of Medical Psychology (U.S., E.G., K.K., H.-J.S.), Diabetes Research Institute (Y.S.-N., A.H., F.A.G), and Medical Institute of Environmental Hygiene (H.-W.B.), Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany.

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Fig. 1. Time schedule of each experimental session on 5 consecutive days.

indicates times at which 20 ml of blood was drawn to measure levels of insulin (INS), glucagon, adrenaline, noradrenaline, and cortisol at minutes -24, 24, 48, and 72.

indicates times at which 20 µl of blood was drawn for measurement of blood glucose. CS = conditioned stimulus; S = symptom list; SP = substance perception; Min* = minutes relative to injection.

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Fig. 2. Blood glucose (mg/dl) on days 1 to 4 of the acquisition phase. Mean (M) and SEM values are shown for groups 1 and 2. Injection was given immediately after blood sampling at minute 0.

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Fig. 3. Blood glucose change (mg/dl) relative to mean (M) baseline level during the test phase (day 5) under CS–saline in groups 1 and 2. Top, Cumulative change over the 13 post-CS measurement points (mean ± SEM). Baseline level is also shown. Bottom, Change per measurement point. Pre-CS measurements (minutes -24 to -6) are interconnected by dotted lines; post-CS measurements are interconnected by solid lines. Results of descriptively conducted Mann-Whitney U tests: [*] = p < .10; * = p < .05.

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Fig. 4. Insulin and cortisol on days 1 to 5 in groups 1 and 2. Left, Insulin change (mU/liter). Difference from baseline value (minute -24). Mean (M) and SEM values are given. Baseline (BA) values are also shown. See break of y axis at day 5. Right, Cortisol change (µg/dl). Difference from baseline value (minute -24). Mean and SEM values are given. BA values are also shown. See break of y axis at day 5. Results of descriptively conducted Mann-Whitney U tests: [*] = p < .10; * = p < .05; *** = p < .001.

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Fig. 5. Number of symptoms. Difference from baseline value (minute -24) on days 1 to 5 in groups 1 ( ${blacksquare}$ ) and 2 ( ${circ}$ ). Mean (M) ± SEM baseline (BA) values are given. Left, Neuroglycopenic score. Middle, Autonomic score. Right, Total number of symptoms score. Mean ± SEM values are given. Results of descriptively conducted Mann-Whitney U tests: [*] = p < .10; * = p < .05; ** = p < .01; *** = p < .001.