Hill, David A.
Beta-adrenergic receptor sensitivity, autonomic balance and serotonergic activity in practitioners of Transcendental Meditation.

Order No.9000435

The aim of this thesis was to investigate the acute autonomic effects of the Transcendental Meditationå Program (TM) and resolve the conflict arising from discrepant neurochemical and psychophysiological data. Three experimental investigations were performed.

The first examined beta sub 2-adrenergic receptors (AR's) on peripheral blood lymphocytes, via [I super {125}] iodocyanopindolol binding, in 10 male mediating and 10 age matched non-meditating control subjects, to test the hypothesis that the long-term practice of TM and the TM Sidhiå Program (TMSP) reduces end organ sensitivity to adrenergic agonists. Independent two-tailed t tests revealed no significant differences in either B sub {max} (t(9) = 0.073), or K sub {D} (t(9) = 0.319). However, the TM group had a reduced percentage of high affinity receptors (t(9) = -3.375, p <.01).

The second investigated respiratory sinus arrhythmia (an indirect measure of cardiac Parasympathetic Nervous System tone), and skin resistance (a measure of Sympathetic Nervous System tone) during periods of spontaneous respiratory apneusis, a phenomenon occurring during TM that is known to mark the subjective experience of "transcending". No detectable changes in heart rate or phasic skin resistance were seen at these times.

The third was a within subject investigation of the acute effects of the TMSP on 5-hydroxytryptamine (5-HT) activity. Platelet 5-HT was assayed by High Pressure Liquid Chromatography with electrochemical detection, plasma prolactin (PL) and lutenizing hormone (LH) by radioimmunoassay, tryptophan by spectrofluorimetry, and alpha-1-acid glycoprotein (AGP, a modulator of 5-HT uptake) by radial immunodiffusion assay. Two- tailed dependent t tests revealed significant reductions in platelet 5-HT (t(22) = 4.37, p < 0.001) and PL (t(24) = 4.47, p < 0.001), with no changes in tryptophan or AGP. Years practicing TM was negatively correlated (r = -0.5, p < 0.01) with post TM PL levels and positively correlated (r = 0.51, p < 0.02) with the 5-HT change score.

These results support the conclusions that the long-term practice of the TM and TMSP is associated with a down regulation of the Beta sub 2 AR on peripheral blood lymphocytes, and that during the acute experience of transcending both divisions of the Autonomic Nervous System are attenuated. The results also provide preliminary evidence to support the hypothesis that TM is associated with acutely reduced hypothalamic and peripheral serotonergic activity. Source: DAI, 50, no. 08B, (1989): 3330


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