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Human brain and spinal cord scan after intracerebroventricular administration of iodine-123 morphine
Null. Med. Biol. Vol. 16, No. 5, pp. 505-509, ht. J. Radiar. Appl. Inslrum. Part B
0883-2897/89 $3.00 + 0.00 Copyright c 1989 Maxwell Pergamon Macmillan plc
1989
Printed in Great Britain. All rights reserved
Human Brain and Spinal Cord Scan after Intracerebroventricular Administration of Iodine- 123 Morphine J. A. M. TAFANI,‘*
Y. LAZORTHES,3 B. DANET,2 J. C. VERDIE,3 J. P. ESQUERRE,’ J. SIMON’ and R. GUIRAUD’
‘Service Central de Midecine Nuclkaire, CHU F’urpan, 31052 Toulouse Cedex, %ervice de Mkdecine Nuclbaire, CHU Rangueil, Toulouse and ‘Clinique de Neurochirurgie, CHU Rangueil, Toulouse, France (Received 20
October
1988)
[‘231]iodomorphine (IMPH) was administered intracerebroventriculary (i.c.v.) in eight patients treated by i.c.v. morphinotherapy (i.c.v.m.). Scans obtained by y-scintigraphy over 1h post-injection showed only a slight diffusion of IMPH beyond the ventricular system, particular attention being paid to the spinal cord. These data agree well with induced i.c.v.m. analgesia (mean latency 20 min) and biological results such as HPLC assay of morphine in the lumbar cerebrospinal fluid, supporting the action of morphine only on the central opiate receptors.
Introduction Local intracerebroventricular morphine (i.c.v.m.) administration in the treatment of pain from chronic intractable cancer is a new neurosurgical technique that is very effective, totally conservative and not very invasive (Roquefeuil et al., 1983; Lazorthes et al., 1985). Although the effectiveness of analgesia induced by i.c.v.m. has been clearly demonstrated, the neurophysiological mechanism is still open to debate, especially with regard to the sites of action of i.c.v.-administered morphine. Are the central structures with abundant opiate receptor sites involved, such as the walls of the third and fourth ventricles (Akaihe et al., 1978; Tsou and Jong, 1964; Dickenson et al., 1979; Yaksh and Rudy, 1978) or are some spinal structures also reached by morphine diffusion and implicated in the intense and diffuse analgesia observed after i.c.v.m.? To investigate the kinetics of morphine diffusion into the human central nervous system and its correlation with the induced analgesia (latency, duration) we studied the isotopic transit of [1231]iodomorphine (IMPH) in eight patients after i.c.v. administration.
Materials and Methods (I) Patients The study was carried out in eight patients suffering from intractable chronic pain of cancerous origin *Author for correspondence.
who were treated by i.c.v. morphinotherapy via a small S.C.access port (0.1 mL Vygon) connected to a ventricular catheter placed in the frontal horn of the lateral ventricle as close as possible to the foramen of Monro. At the time of the study, i.c.v.m. had been administered for at least 8 days and the individual daily doses had been determined. (Dose range 0.14 mg/24 h, mean 0.70 mg/24 h = 2 pmol, injected in the same volume (1 mL3 + 0.5 mL3) that IMPH.) (2) Radiotracer (A) Preparation, puriJication and identification of MPH. Morphine was iodated using iodogen as the
oxidizing reagent (Simiodx Solabco). Briefly, 5 PL of morphine chlorhydrate solution (1 mg/mL) was added to 100 p L of a buffer composed of 25 nM sodium phosphate, 40% methanol, pH 5.5 and 1 mCi carrier-free Na1231(ORIS Industrie). Two “beads” of Simiod” were successively added at an interval of 1 min with stirring. The reaction was terminated by adding 20 PL of sodium metabisulfite (1 mg/mL). The total radioiodination reaction mixture was then immediately applied to a Bondapack- 18 column. Elution (with 1% acetic acid, 40% methanol, pH 4.5) was carried out at 3 mL/min using a Waters apparatus. Absorbance was monitored at 285 nm. Fractions of 1.5 mL were collected and the radioactivity was measured in a y counter (Packard-Autogamma 500); the fractions were then evaporated and diluted so5
J. A. M. TAFANIet al
506
in saline. Sterilizing filtration was performed through a 0.22 pm filter (Millex Millipore) into a sterilized vial. Pure IMPH (99%) was obtained with high specific activity (500 Ci/mmol). (B) In-vitro binding assay and analgesic activity of iodomorphine. A classical in -vitro binding study was
carried out on tissue with abundant p-type opiate receptors, i.e. the membrane fraction of rabbit cerebellum. The affinity constant K, was determined from the iodomorphine concentration yielding 50% inhibition of specific binding of [3H]etorphine (Kd = 0.1 nM) used at 0.5 nM. Analgesic activity was evaluated by electric stimulation of rat tail after lumbar intrathecal injection of iodomorphine using the technique of Yaksh and Ruddy (1977). (3) Protocol of injection and scans Each patient received an i.c.v. injection of IMPH (OS-1 mCi = l-2 nmol) diluted in 1 mL of saline. The access port was then washed by another injection of saline (0.5 mL). The molar ratio of iodinated derivative to morphine in the i.c.v. injection was O.5-1O-3 Serial y camera scans (Gammatome II Sopha Mtdical) of brain and spinal cord were then performed for I h after i.c.v. IMPH injection (average 30 scans per hour). Data processing was done on an Apex 009 Elscint processor.
Results IMPH binding was found to be 10 times lower However, the analgesic activity was maintained in the rat since the dose-response curve (data not shown) was identical to that obtained with morphine. The scans showed that: (Ki ~50 nM) than that of morphine.
-in
all cases migration of radioactivity away from the brain was very slight (Fig. 1). No radioactivity was measurable in the spine before 30min postinjection (Fig. 2). After 1 h, only 5% of the injected activity was found in the spine (Fig. 3) and this diffusion did not go beyond the thoracic region (Fig. 4). -90% of the radioactivity remained localized in the brain with two types of diffusion.
(1) slight parenchymal
diffusion (Fig. 5), with most radioactivity localized in the third and fourth ventricules. (2) stronger parenchymal diffusion (up to 50%). In this case, the lateral ventricles were more radioactive than the third and fourth ventricles (Fig. 6).
Discussion These results agree with various clinical and biochemical studies (Lazorthes et al., 1988; Caute et al., 1988) tending to demonstrate that the intense and diffuse analgesia reported with i.c.v.m. is independent of any direct action of morphine diffused into the spine. In our study, no significant radioactivity was detectable in the spinal cord before 30 min post-injection although the mean latency of induced i.c.v.m. analgesia is 20min (Lazorthes et al., 1988). Parenchymal diffusion was strong (up to 50%, Fig. 6) when the ventricular catheter was placed in the occipital horn. In this case, the lateral ventricle (where the surface of exchange is the greatest) collected the radioactivity, explaining the greater parenchymal diffusion observed. In contrast, when the ventricular catheter was placed close to the foramen of Monro, or sometimes catheterized into the third ventricle, parenchymal diffusion was slight (Fig. 5) and the third and fourth ventricles remained the most radioactive after 1 h. The choice of IMPH as a radiotracer in studying diffusion after i.c.v. administration is justified by: -its biochemical and pharmacological properties (i.e. binding capacity and analgesic activity). -the fate of the molecule in the organism, which is probably the same as that of morphine as indicated by some of our data: (1) after 30 min in 50% of the patients, an image of the liver was observed (Fig. 4) corresponding to hepatic impounding after venous recovery. (2) no thyrdid or renal image was seen in any of the patients, proving the absence of detectable deiodation of IMPH during the study. Moreover, the absence of deiodination was previously checked in -vitro by maintaining iodomorphine in 0.9% NaCl for 2 h at 37°C.
Figs 1-6. (Opposife) Human brain and spinal cord 7 camera images after i.c.v. [‘*‘I]iodomorphine administration. Fig. 1. Side view-1 5 min post-injection. Fig. 2. Side view-30 min post-injection. Fig. 3. Rear view-60 min post-injection. Fig. 4. Rear view-60 min post-injection. Fig. 5. Side view-60 min post-injection. Fig. 6. Side view-60 min post-injection.
(21
(3)
507
2
Intracerebroventricular [1231]iodomorphineadministration These preliminary results on the kinetics of iodomorphine administered i.c.v. agree well with clinical i.c.v.m. data. However, this protocol did not allow an exact determination of the location of the binding sites. This would require the use of labeled molecules that are much more precisely adapted, i.e. agonist peptides or their non-degradable analogues (Dago, FK 33 824), as well as a more efficient technique such as single photon computed emission tomography instead of planar 7 scintigraphy.
509
after lumbar intrathecal administration of isobaric and hyperbaric solutions for cancer pain. Pain 32:141; 1988. Dickenson, A. H.; Oliveras, J. L.; Besson, J. M. Role of the nucleus raphe magnus in opiate analgesia as studied by the microinjection technique in the rat. Brain Res. 170:95; 1979.
Lazorthes, Y.; Verdie, J. C.; Bastide, R.; Lavados. R.; Descouens, D. Spinal versus intraventricular chronic opiate administration with implantable drug delivery devices for chronic aain. ADDI. Neuroohvsiol. 48:234: 1985. Lazorthes. Y., Verdik: J. C.; ‘Caute, B.; Maranho, R.; Tafani, J. A. M. Intracerebroventricular morphinotherapy for control of cancer pain. Prog. Brain Res. 77:397-407; 1988.
References Akaike, A.; Shibata, T.; Satoh, M., Takadi, H. Analgesia induced by microinjection of morphine and electrical stimulation of the nucleus reticularis paragigantocellularis of the rat medulla oblongata. Neuropharmacology. 171775; 1978.
Caute, B.; Monsarrat, B.; Guarderes, C.; Verdie, J. C.; Lazorthes, Y.; Cros, J.: Bastide. R. CSF morphine levels
Roquefeuil, B.; Benezech, J.; Batier, C.; Blanchet, P.; Gros, C.; Mathieu-Daude, J. C. Inter& de l’analgbsie morphinique par voie ventriculaire dans les algies rebelles ntoplasiques. Neurochirurgie 29: 135; 1983. Tsou, K.; Jang, C. S. Studies of the site of analgesic action of morphine by intracerebral microinjection. Scient. Sinica 19:1099; 1964.
Yaksh, T. L.; Rudy, 1. A. Narcotic analgetics:CNS sites and mechanisms of action as revealed by intracerebral injection techniques. Pain 4:299; 1978.
0883-2897/89 $3.00 + 0.00 Copyright c 1989 Maxwell Pergamon Macmillan plc
1989
Printed in Great Britain. All rights reserved
Human Brain and Spinal Cord Scan after Intracerebroventricular Administration of Iodine- 123 Morphine J. A. M. TAFANI,‘*
Y. LAZORTHES,3 B. DANET,2 J. C. VERDIE,3 J. P. ESQUERRE,’ J. SIMON’ and R. GUIRAUD’
‘Service Central de Midecine Nuclkaire, CHU F’urpan, 31052 Toulouse Cedex, %ervice de Mkdecine Nuclbaire, CHU Rangueil, Toulouse and ‘Clinique de Neurochirurgie, CHU Rangueil, Toulouse, France (Received 20
October
1988)
[‘231]iodomorphine (IMPH) was administered intracerebroventriculary (i.c.v.) in eight patients treated by i.c.v. morphinotherapy (i.c.v.m.). Scans obtained by y-scintigraphy over 1h post-injection showed only a slight diffusion of IMPH beyond the ventricular system, particular attention being paid to the spinal cord. These data agree well with induced i.c.v.m. analgesia (mean latency 20 min) and biological results such as HPLC assay of morphine in the lumbar cerebrospinal fluid, supporting the action of morphine only on the central opiate receptors.
Introduction Local intracerebroventricular morphine (i.c.v.m.) administration in the treatment of pain from chronic intractable cancer is a new neurosurgical technique that is very effective, totally conservative and not very invasive (Roquefeuil et al., 1983; Lazorthes et al., 1985). Although the effectiveness of analgesia induced by i.c.v.m. has been clearly demonstrated, the neurophysiological mechanism is still open to debate, especially with regard to the sites of action of i.c.v.-administered morphine. Are the central structures with abundant opiate receptor sites involved, such as the walls of the third and fourth ventricles (Akaihe et al., 1978; Tsou and Jong, 1964; Dickenson et al., 1979; Yaksh and Rudy, 1978) or are some spinal structures also reached by morphine diffusion and implicated in the intense and diffuse analgesia observed after i.c.v.m.? To investigate the kinetics of morphine diffusion into the human central nervous system and its correlation with the induced analgesia (latency, duration) we studied the isotopic transit of [1231]iodomorphine (IMPH) in eight patients after i.c.v. administration.
Materials and Methods (I) Patients The study was carried out in eight patients suffering from intractable chronic pain of cancerous origin *Author for correspondence.
who were treated by i.c.v. morphinotherapy via a small S.C.access port (0.1 mL Vygon) connected to a ventricular catheter placed in the frontal horn of the lateral ventricle as close as possible to the foramen of Monro. At the time of the study, i.c.v.m. had been administered for at least 8 days and the individual daily doses had been determined. (Dose range 0.14 mg/24 h, mean 0.70 mg/24 h = 2 pmol, injected in the same volume (1 mL3 + 0.5 mL3) that IMPH.) (2) Radiotracer (A) Preparation, puriJication and identification of MPH. Morphine was iodated using iodogen as the
oxidizing reagent (Simiodx Solabco). Briefly, 5 PL of morphine chlorhydrate solution (1 mg/mL) was added to 100 p L of a buffer composed of 25 nM sodium phosphate, 40% methanol, pH 5.5 and 1 mCi carrier-free Na1231(ORIS Industrie). Two “beads” of Simiod” were successively added at an interval of 1 min with stirring. The reaction was terminated by adding 20 PL of sodium metabisulfite (1 mg/mL). The total radioiodination reaction mixture was then immediately applied to a Bondapack- 18 column. Elution (with 1% acetic acid, 40% methanol, pH 4.5) was carried out at 3 mL/min using a Waters apparatus. Absorbance was monitored at 285 nm. Fractions of 1.5 mL were collected and the radioactivity was measured in a y counter (Packard-Autogamma 500); the fractions were then evaporated and diluted so5
J. A. M. TAFANIet al
506
in saline. Sterilizing filtration was performed through a 0.22 pm filter (Millex Millipore) into a sterilized vial. Pure IMPH (99%) was obtained with high specific activity (500 Ci/mmol). (B) In-vitro binding assay and analgesic activity of iodomorphine. A classical in -vitro binding study was
carried out on tissue with abundant p-type opiate receptors, i.e. the membrane fraction of rabbit cerebellum. The affinity constant K, was determined from the iodomorphine concentration yielding 50% inhibition of specific binding of [3H]etorphine (Kd = 0.1 nM) used at 0.5 nM. Analgesic activity was evaluated by electric stimulation of rat tail after lumbar intrathecal injection of iodomorphine using the technique of Yaksh and Ruddy (1977). (3) Protocol of injection and scans Each patient received an i.c.v. injection of IMPH (OS-1 mCi = l-2 nmol) diluted in 1 mL of saline. The access port was then washed by another injection of saline (0.5 mL). The molar ratio of iodinated derivative to morphine in the i.c.v. injection was O.5-1O-3 Serial y camera scans (Gammatome II Sopha Mtdical) of brain and spinal cord were then performed for I h after i.c.v. IMPH injection (average 30 scans per hour). Data processing was done on an Apex 009 Elscint processor.
Results IMPH binding was found to be 10 times lower However, the analgesic activity was maintained in the rat since the dose-response curve (data not shown) was identical to that obtained with morphine. The scans showed that: (Ki ~50 nM) than that of morphine.
-in
all cases migration of radioactivity away from the brain was very slight (Fig. 1). No radioactivity was measurable in the spine before 30min postinjection (Fig. 2). After 1 h, only 5% of the injected activity was found in the spine (Fig. 3) and this diffusion did not go beyond the thoracic region (Fig. 4). -90% of the radioactivity remained localized in the brain with two types of diffusion.
(1) slight parenchymal
diffusion (Fig. 5), with most radioactivity localized in the third and fourth ventricules. (2) stronger parenchymal diffusion (up to 50%). In this case, the lateral ventricles were more radioactive than the third and fourth ventricles (Fig. 6).
Discussion These results agree with various clinical and biochemical studies (Lazorthes et al., 1988; Caute et al., 1988) tending to demonstrate that the intense and diffuse analgesia reported with i.c.v.m. is independent of any direct action of morphine diffused into the spine. In our study, no significant radioactivity was detectable in the spinal cord before 30 min post-injection although the mean latency of induced i.c.v.m. analgesia is 20min (Lazorthes et al., 1988). Parenchymal diffusion was strong (up to 50%, Fig. 6) when the ventricular catheter was placed in the occipital horn. In this case, the lateral ventricle (where the surface of exchange is the greatest) collected the radioactivity, explaining the greater parenchymal diffusion observed. In contrast, when the ventricular catheter was placed close to the foramen of Monro, or sometimes catheterized into the third ventricle, parenchymal diffusion was slight (Fig. 5) and the third and fourth ventricles remained the most radioactive after 1 h. The choice of IMPH as a radiotracer in studying diffusion after i.c.v. administration is justified by: -its biochemical and pharmacological properties (i.e. binding capacity and analgesic activity). -the fate of the molecule in the organism, which is probably the same as that of morphine as indicated by some of our data: (1) after 30 min in 50% of the patients, an image of the liver was observed (Fig. 4) corresponding to hepatic impounding after venous recovery. (2) no thyrdid or renal image was seen in any of the patients, proving the absence of detectable deiodation of IMPH during the study. Moreover, the absence of deiodination was previously checked in -vitro by maintaining iodomorphine in 0.9% NaCl for 2 h at 37°C.
Figs 1-6. (Opposife) Human brain and spinal cord 7 camera images after i.c.v. [‘*‘I]iodomorphine administration. Fig. 1. Side view-1 5 min post-injection. Fig. 2. Side view-30 min post-injection. Fig. 3. Rear view-60 min post-injection. Fig. 4. Rear view-60 min post-injection. Fig. 5. Side view-60 min post-injection. Fig. 6. Side view-60 min post-injection.
(21
(3)
507
2
Intracerebroventricular [1231]iodomorphineadministration These preliminary results on the kinetics of iodomorphine administered i.c.v. agree well with clinical i.c.v.m. data. However, this protocol did not allow an exact determination of the location of the binding sites. This would require the use of labeled molecules that are much more precisely adapted, i.e. agonist peptides or their non-degradable analogues (Dago, FK 33 824), as well as a more efficient technique such as single photon computed emission tomography instead of planar 7 scintigraphy.
509
after lumbar intrathecal administration of isobaric and hyperbaric solutions for cancer pain. Pain 32:141; 1988. Dickenson, A. H.; Oliveras, J. L.; Besson, J. M. Role of the nucleus raphe magnus in opiate analgesia as studied by the microinjection technique in the rat. Brain Res. 170:95; 1979.
Lazorthes, Y.; Verdie, J. C.; Bastide, R.; Lavados. R.; Descouens, D. Spinal versus intraventricular chronic opiate administration with implantable drug delivery devices for chronic aain. ADDI. Neuroohvsiol. 48:234: 1985. Lazorthes. Y., Verdik: J. C.; ‘Caute, B.; Maranho, R.; Tafani, J. A. M. Intracerebroventricular morphinotherapy for control of cancer pain. Prog. Brain Res. 77:397-407; 1988.
References Akaike, A.; Shibata, T.; Satoh, M., Takadi, H. Analgesia induced by microinjection of morphine and electrical stimulation of the nucleus reticularis paragigantocellularis of the rat medulla oblongata. Neuropharmacology. 171775; 1978.
Caute, B.; Monsarrat, B.; Guarderes, C.; Verdie, J. C.; Lazorthes, Y.; Cros, J.: Bastide. R. CSF morphine levels
Roquefeuil, B.; Benezech, J.; Batier, C.; Blanchet, P.; Gros, C.; Mathieu-Daude, J. C. Inter& de l’analgbsie morphinique par voie ventriculaire dans les algies rebelles ntoplasiques. Neurochirurgie 29: 135; 1983. Tsou, K.; Jang, C. S. Studies of the site of analgesic action of morphine by intracerebral microinjection. Scient. Sinica 19:1099; 1964.
Yaksh, T. L.; Rudy, 1. A. Narcotic analgetics:CNS sites and mechanisms of action as revealed by intracerebral injection techniques. Pain 4:299; 1978.