Department of Medicine, University of California, Irvine, California, U.S.A.

Transcription

1 PPR 16 RSTRUTON O LOO LOW N TRNSCNNTL MTTON R. VNN,.. WLSON, W.R. SMT, and M. MORTON epartment of Mediine, University of California, rvine, California, U.S.. Mar ked dereases in hepati and renal blood flow, and a slight inrease in ardia output, were found during Transendental, suggesting that a large inrease in erebral blood flow ours during the pratie.-tors The following is the text of the original paper whih was presented in part to the fall meeting of the merian Physiologial Soiety, San raniso, California, U.S.., Otober Transendental indues rapid physiologial hanges whih aompany a mental state whih has been desribed as wakeful. Cirulation is sensitively and harateristially affeted by behavioral state, and the perfusion of some organs, partiularly brain and musle, is losely related to their level of ativity. The present study was designed to identify possible onsistent effets of TM on blood flow distribution in order to help us understand the mehanism oftm and its relationship to other forms of behavior. Total ardia output, and renal and hepati blood flow were studied in 24 subjets. Cardia output was found to inrease slightly and renal and hepati blood flow to deline markedly during TM; hepati blood flow remained low 3 minutes after essation of meditation. in ontrols was assoiated with a deline in renal blood flow; no onsistent hange developed in ardia output or hepati blood flow. Pulse did not hange in either ontrols or meditators and adrenoortial ativity in the subjets was low throughout the experiment. The blood flow hanges observed indiate a probable large inrease in erebral blood flow during TM. The pattern and magnitude of blood flow redistribution observed differ from those ourring during relaxation and sleep. Transendental (or TM) is a widely pratied mental tehnique whih requires no physial or mental effort (9). The physiologial state indued by TM, desribed as ''wakeful hypometabolism'' ( 13), has been extensively studied physiologially. There is about a 16% derease in both oxygen onsumption and arbon dioxide elimination in 3 minutes; blood pressure remains onstant, and blood latate delines ( 13). There is an inrease in entral and frontal slow wave ativity and a distintive inrease of oherene in the reorded from different regions of the salp (1, 13). drenoortial ativity delines (7). Regular pratie of TM has been shown to be assoiated with lower resting blood pressure levels in essential hypertensives ( 14). The observed aute dereases of blood latate and 2 onsumption, the longitudinal effet of lowered blood pressure, plus the known exquisite sensitivity of ardia output and other irulatory parameters to behavioral states (2, 4), led us to undertake a study of the regional distribution of blood flow during TM. Suh a study may help in the understanding of the mehanism of the TM-indued physiologial hanges, some of whih are diretly relevant to health. We were also interested in omparison of blood flow hanges in TM to those that our during 787

2 SCNTC RSRC ON T TRNSCNNTL MTTON N TM-S PRORMM, VOL. 2 ordinary relaxation or sleep, forms of behavior whose relationship to TM is not adequately understood (8). MTOS Our approah was to measure total ardia output and those organ blood flows whose perent of total ardia output is greatest. Speifially, ardia output, hepati blood flow, and renal blood flow were measured in 24 normal, young, adult subjets divided into two groups: a group of ontrols who volunteered for the study prior to learning TM and a group who had been regularly pratiing TM 2 minutes twie daily for periods of 4 months to 4 years. ll subjets were familiarized with the laboratory, its personnel and the purpose and ourse of the experiment on an oasion previous to the day of the experiment. The study methods hosen were suh as to be minimally invasive and yet apable of yielding reliable blood flow hanges. Clearane methods were used for the hepati and renal studies and dye dilution was used for the measurement of ardia output. Prior to the beginning of the observations, arterial and venous atheters were plaed into the arm of eah subjet following topial anaesthesia with 1% lidoaine, and leads were attahed for monitoring the. fter a 2 1/2 hour wait to allow any hanges assoiated with atheter plaement to disappear, subjets were seated omfortably in a hair behind a urtain, lights were dimmed and experimental measurements begun. ll injetions and blood sampling were aomplished via extension lines attahed to the subjet and passed through the urtain. igure 1 shows the hronologial ourse of the experiment and the sequene and timing of injetions and blood sampling. The experiment was divided into 3 parts, eah of 4 minutes duration. uring the pre-relaxation or pre-meditation period, both ontrols and pratitioners sat omfortably with their eyes open. uring the relaxation or meditation period, ontrols were asked to lose their eyes and relax maximally, whereas the TM pratitioners used the TM tehnique. for the ~ontrols is their normal behavior under these irumstanes and should not be onfused with any speifi tehnique of relaxation. The post-period, like the preperiod, onsisted of sitting, eyes open. Renal plasma flow was estimated from the learane of hippuran (12). venous injetion of hippuran was made 1 minutes into eah period. epati blood flow was estimated from the learane of 99 mt-sulfur olloid, injeted 18 minutes into eah period (3). sotope learanes were determined from multiple 1 samples of arterial blood withdrawn beginning 2 minutes into the period, and thereafter at 22, 23, 24, 26, and 3 min-, utes. To evaluate the possibility of signifiant traer remaining from the previous period in the meditation and post-meditation periods, blood sampling for bakground and 99 mt was aomplished just prior to injetion of the isotopes in the meditation and post-meditation periods. The ounts obtained showed that interferene from the previous period was negligible. One samples of whole blood were ounted in a Nulear Chiago Well ounter with ounting times seleted to give an average S.. of± 3% in the differenes in ounts between dupliates. The test doses used were 1-2t-tC of hippuran and 2-5 t-tc of 99 mt-sulfur olloid.. 1. PR-MTTON YS OPN MTTON OR "RLTON" POST-MTTON YS OPN PPURN NCTONS 99mT..SULUR LOO SMPLN CRC OUTPUT MSURMNT MNUTS

3 or renal flow, single exponential analysis was applied to the data obtained from the six samples; renal learane, C, is related to the injeted dose,, the interept,, and the slope, m, of the semilogarithmi disappearane urve (12):. lm C=- (1) sine represents the total dilution volume, V, this may be rewritten: C =Vm (2) Sine it is unlikely that V will hange during either the meditation or post-meditation periods, perent hange in flow during these periods (ompared to pre-meditation) is therefore equal to the perent hanges in slope: (3) where m 2 is the slope during meditation (or postmeditation) and m 1 is the slope during the premeditation period. The disappearane of 99 mt-sulfur olloid is desribed by a biexponential urve after exlusion of the mixing phase whih is omplete within two minutes (3). The early or rapid phase, whih is of six minutes duration, ommening two minutes after injetion, is a monoexponential and allows reasonably aurate determination of liver blood flow (3). ene, during this early phase equation 3 may be utilized to alulate perent hange of liver blood flow. Possible limitations of this method inlude signifiant extrahepati removal (sine 99 mt-sulfur olloid is removed by the retiuloendothelial system) or a signifiantly redued extration effiieny for the olloid. owever, in normal individuals extrahepati removal is minimal and the olloid extration effiieny is over 9% (3). The time of bolus injetion of.5 ml of a 5 mg% solution of indoyanine green and subsequent samplings for measurement of ardia output are also shown in figure 1. Cardia output studies were perfor;med on different sets of ontrols and pratitioners from those groups studied for renal and hepati flows. Cardia output values were alulated by omputer integration of dye onentration versus time urves (Lyons Medial nstrument Corporation, Model CC-) aording to the dye dilution method. Mean± S.. L M Mean± S.. p<.os TL 1 RNL LOO LOW, Oft CN ( PPURN) p<.ool S -S ± 7" 1M S6 -Sl ± 1* TL ± S± 11 PTC LOO LOW, Ofo CN (99mT- SULUR COLLO) Mean± S.. L M Mean± S.. p<.os S - S ± S 1M -S9-31 s S -8S -32 ± 16* S 8 ± ± s 789

4 SCNTC RSRC ON T TRNSCNNTL MTTON N TM-S PRORMM, VOL. 2 TL 3 CRC OUTPUT (L/MN) Pre-relaxation Mean± S ± ± ± ± ± ± TM Pre-meditation Mean± S ± ± ±.31* 6.81 ±.so 5.69 ± ±.28 p <.1 (ompared to average of prevalues) RSULTS Table 1 shows the perent hange in renal blood flow from pre-meditation levels in eah of the meditation and post-meditation periods for ontrols and pratitioners. ndividual subjets are shown along with the value for the mean hange in eah period. Signifiant (t-test on paired differenes) dereases in renal flow, denoted by asterisks, were observed in both ontrols and pratitioners during relaxation and meditation respetively. low values in both ontrols and pratitioners returned to pre-levels in the post-period. n Table 2 the data for both individual and mean hepati flow hanges are presented. epati flow markedly dereases during the meditation period in the pratitioners of TM and remains very low in the post-meditation period; no signifiant hange was noted in ontrols. n Table 3 ardia output values for the 11 individual subjets are shown. Cardia output rose signifiantly in pratitioners of TM during meditation only; no hanges ourred in ontrols. Sine pulse and plasma ortisol (7) did not hange signifiantly during the experiment in either ontrols or pratitioners, it is unlikely, that the tehniques of measurement per se affeted the results. SCUSSON n summary, TM is aompanied by signifiant delines in renal (27%) and hepati blood flow (32%) oupled with a small inrease in total ardia output ( 15%) during the meditation period. This set of hanges implies a onsiderable inrease in blood flow to other organs. Sine brain and/or musle blood flow aount for the major portion of total blood flow after renal and hepati ontributions have been subtrated (4), it is likely that flow to either or both of these organs inreased. Only renal flow hanged in ontrols. Therefore the pattern and magnitude of blood flow redistribution during TM seem to be different from that ourring during simple relaxation. The hanges in TM also differ from those in other behavioral states suh as slow wave sleep: erebral blood flow inreases only slightly (1%); musle blood flow delines (15); and a onsistent hange in ardia output is not losely assoiated with either slow wave or RM sleep {5, 15). No diret measurements have been made at this time of musle blood flow during TM. owever, dereased musular ativity indiated by dereased M ativity during TM (6, 8), has been orrelated losely under resting onditions with dereased musle blood flow (6). Total musle blood flow delines during RM sleep, whih is also harater.:. 79

5 ized by a redued level of M ativity (15). t is likely, therefore, that inreased erebral blood flow aounts for the major portion of the redistributed flow during TM (and to some extent during relaxation). The magnitude of this inrease is on the order of 75% or greater under the assumption of unaltered musle blood flow; if musle blood flow delines the inrease in erebral blood flow is even greater. This large inrease is omparable under natural onditions only to the magnitude of the inrease observed during RM sleep (8%) (1, 16). Sine the brain is almost unique among organs in that both regional and total blood flow are very losely orrelated with the level of metaboli (and neural) ativity ( 4, 11), it seems like! y that erebral ativity during TM is onsiderably inreased, perhaps explaining the earlier subjetive reports of the TM-indued mental state as one of enhaned wakefulness ( 13). ereased flow of blood to renal and hepati iruits in order to supply inreased brain blood flow in TM seems to be an example of the operation of a mehanism generally invoked in states of aute need by one or more speifi organ system(s); renal and hepati onstrition also ours, for example, during the diving reflex (4) and during stress (2). Sine erebral blood is ontrolled to some extent by blood p ( 11), it is of interest that TM is assoiated with development of a mild aidosis (13). RRNCS 1. NQUT,.-P The spetral analysis of the during Transendental. letroenephalographyand Clinial Neurophysiology 35: RO, The idney, p London: utterworths. 3. CRST,.., and CUUR, T Measurement of hepati blood flow. Seminars in Nulear Mediine 2: OLOW,., and NL, Cirulation. London: Oxford University Press. 5. ROLLMN, Physiologial variations in the ardia output of man. merian ournal of Physiology 95: UUC, Musle lood low, pp msterdam: Swets. 7. VNN, R.; WLSON,..; VNRLN,.; and LVN, S Plasma prolatin and ortisql during Transendental. The ndorine Soiety (abstrat). 8. NLLOS,., and LUS, The Psyhobiology of Transendental, p. 11. Menlo Park, California: enjamin. 9. MRS MS YO The Siene of eing and rt of Living, pp London: nternational SRM Publiations. 1. MNOL, R.; SOOLO, L.; COMR,.; and TY, S. S The effets of sleep on the erebral metabolism of normal young men. ournal of Clinial nvestigation 34: MYR,., and WLC, Cerebral blood flow and metabolism. Progress in rain Researh 35: PRTCR, W..; CSTN, R. W.; MC NTYR, W..; and, Correlation of renal blood flow determined by the single injetion of hippuran -131 with diret measurement of flow. merian eart ournal 7: WLLC, R.., et al wakeful hypometaboli state. merian ournal of Physiology 221: WLLC, R.., et al ereased blood pressure in hypertensive subjets who pratied meditation. Supplement to Cirulation 45 and 46: RS,..; MOOR,.; and WOOTN, C ifferential regulation of blood flow to red and white musles in sleep and defene behavior. merian ournal of Physiology 217: RVTC, M., and SCS, ffetsofslow wave sleep and RM on erebral blood flow in ats. ournal of Neurohemistry 15: