Masao Kobori

The acupuncture point and its connecting central pathway for producing acupuncture analgesia

Characteristics of the acupuncture point in producing acupuncture analgesia (AA) were examined by the inhibition of noxious responses in the brain stem reticular formation, potentials, and neuronal activity in the dorsal periaqueductal central gray (D-PAG), and analgesia caused by low frequency stimulation of the acupuncture point. As a result, stimulation of the muscle beneath the acupuncture point was found to be effective in producing AA. AA measured by tail flick, vocalization, and writhing tests was abolished by hypophysectomy, and by antiserum of beta-endorphin administered into the 3rd ventricle. The pathway from the D-PAG to the anterior hypothalamus (AA-AH) in the AA afferent pathway from the acupuncture point to the pituitary gland was determined. The lateral hypothalamus, lateral septum, cingulate bundle, dorsal-hippocampus, and habenulo-interpeduncular tract were found, in addition to regions previously found, to belong to the AA afferent pathway. A network of divergence and convergence in their rostral and caudal relations was observed. The AA afferent pathway diverges from the D-PAG, converges to the HP, and then projects to the AA-AH.

Analgesia inhibitory system involvement in nonacupuncture point-stimulationproduced analgesia

Acupuncture analgesia (AA), caused by low-frequency stimulation of an acupuncture point (AP)--in this case the tibial muscle--was augmented. Nonacupuncture analgesia (NAA), caused under certain circumstances by stimulation of a nonacupuncture point (NAP)--in this case the abdominal muscle--was unmasked by lesion in the lateral centromedian nucleus of the thalamus (L-CM) or part of the posterior hypothalamus (I-PH). Stimulation in these regions suppressed the augmented part of the AA and blocked the NAA. These regions were, collectively, given the name analgesia inhibitory system. NAA was abolished, the same as AA, by hypophysectomy. The pathways from the AP and NAP to the pituitary gland were different. AA was naloxone reversible, and NAA was dexamethasone reversible. The analgesia inhibitory system is activated nonspecifically by stimulation of either an AP or NAP. It ascends to the I-PH, thence to the L-CM, and ultimately inhibits the pathway nonspecifically connected to the NAP and AP in the lateral part of the periaqueductal central gray (PAG), without affecting the pathway specifically connected to the AP. Thus, only stimulation of an AP will produce analgesia, whereas stimulation of an NAP will not normally produce analgesia. Stress-induced analgesia (SIA) is produced in a different way than AA or NAA.

AFFERENT AND EFFERENT PATHWAYS IN ACUPUNCTURE ANALGESIA AND THEIR CORRELATION WITH MORPHINE ANALGESIA

Acupuncture afferent pathways were explored by stimulation-produced analgesia, by hypophysectomy, and by lesions which abolished acupuncture, morphine(0.5 mg/kg i.p.), and dorsal periaqueduct stimulation-produced analgesia. Lesion of the anterolateral tract(ALT) blocked morphine analgesia(0.05 μg intrathecal). Descending serotonergic and noradrenergic pain inhibitory systems mediate analgesia.

Efficacy of prostaglandin E1 in combination with volume replacement therapy in the treatment of Hemorrhagic shock in dogs

Abstract Objective: The aim of the present study was to assess the effects of prostaglandin E 1 (PGE 1 ) on hemodynamic and splanchnic blood flow in a canine model of hemorrhagic shock and volume replacement therapy. Methods: Hemorrhagic shock was induced in 14 anesthetized dogs by withdrawing blood into a reservoir until the mean arterial pressure stabilized at 50 mm Hg for 30 minutes. During oligemia, the drawn blood was stored at room temperature in plastic bags containing citrate-phosphate-dextrose solution. The shock period was then terminated and the remainder of the drawn blood was reinfused within a 2-minute period. The dogs were divided into 2 equal groups. Group P received PGE 1 0.1 μg/kg per minute; group S received saline in an amount equal to the diluent in group P (0.6 mL/kg per hour). The efficacy of both therapies in maintaining hemodynamic variables and splanchnic blood flow (renal cortex, renal medulla, liver, and pancreas) was investigated over 180 minutes. Splanchnic blood flow was determined by the hydrogen gas clearance method. Results: Sixty to 180 minutes after resuscitation, the cardiac index and left ventricular stroke work index values in group P were significantly greater than those in group S ( P P P Conclusions: The results of this study in dogs demonstrate that PGE 1 added to volume replacement therapy is a useful adjuvant with respect to hemodynamic and splanchnic recovery in hemorrhagic shock.

Plasma Substitutes for Volume Replacement in Hemorrhagic Shock: Comparison of Low and Medium Molecular Weight Hydroxyethyl Starch

Abstract Objective The aim of this study was to assess the relative efficacy of 2 volume replacement therapies in a canine model of induced hemorrhagic shock. Methods Anesthetized dogs were bled to maintain mean arterial pressure (mAP) at 50 mm Hg for 30 minutes and then administered a single bolus injection of 6% hydroxyethyl starch (HES) with a molecular weight of 70 kd (HES70 group) or 200 kd (HES200 group) at a volume equivalent to the blood withdrawn. We examined the efficacy of both therapies in maintaining hemodynamic variables and splanchnic organ blood flow (ie, blood flow through the renal cortex, renal medulla, liver, and pancreas). Results After resuscitation, hemodynamic variables were better maintained in the HES200 group than in the HES70 group. In particular, HES200 better preserved mAP, cardiac index, mean pulmonary arterial pressure, pulmonary arterial wedge pressure, left ventricular stroke work index, and maximum rate of left ventricular pressure change. In both groups splanchnic organ blood flows decreased significantly after hemorrhagic shock but increased after volume replacement resuscitation. After resuscitation splanchnic organ blood flow was significantly greater in the HES200 group than in the HES70 group ( P Conclusions The results of this study suggest that HES200 is more effective than HES70 as volume replacement therapy in a canine model of hemorrhagic shock, as measured by improvements in hemodynamic variables and splanchnic organ blood flow.

ACUPUNCTURE AND MORPHINE ANALGESIA INHIBITORY SYSTEMS AND ITS CORRELATION WITH MORPHINE TOLERANCE

Two acupuncture analgesia (AA) afferent pathways were identified by lesion of the lateral centromedian nucleus of thalamus(1-CM). One is, and the other is not inhibited by 1-CM during AA, 0.5 mg/kg morphine analgesia(MA) or dorsal periaqueduct central gray stimulation-produced analgesia(d-PAG-SPA). Morphine tolerance might develop in the analgesia inhibitory system.

Regional and systemic hemodynamics during hemodilution with isovolemic hydroxyethyl starch solution alone and in combination with sodium nitroprusside- or isoflurane-induced controlled hypotension in isoflurane-anesthetized dogs

Abstract Objective The aim of the present study was to assess systemic and splanchnic hemodynamics during isovolemic hemodilution and during controlled hypotension induced by sodium nitroprusside (SNP) or isoflurane (ISO) in ISO-anesthetized dogs. Methods : Hemodilution was performed by exchanging blood (20 mL/kg) with isovolemic hydroxyethyl starch solution (6% in saline, molecular weight 70 kd). Hypotension was induced for 90 minutes, with a mean arterial pressure of 70 mm Hg. Results Hemodilution combined with SNP-induced hypotension produced an increased cardiac index (CI) and a maximal left ventricular pressure change (LV dp/dt max ) compared with prehemodilution values. ISO-induced hypotension produced a decreased CI. During the hypotensive period, CI and LV dp/dt max in the SNP group were significantly greater than in the ISO group. In the SNP group, the changes from prehemodilution values in renal cortical and medullary blood flow (RCBF and RMBF) were not significant during conditions of hemodilution and induced hypotension, but liver and pancreatic blood flow (LBF and PBF) were significantly decreased ( P P P Conclusions Results of the present paper suggest that with respect to splanchnic hemodynamic variables, SNP is preferable to ISO as a hypotensive agent during hemodilution.