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An improved instrument for implanting micropellets in the brain
Physiology and Behavior. Vol. 5, pp. 123-124. Pergamon Press, 1970. Printed in Great Britain
BRIEF COMMUNICATION An Improved Instrument for Implanting Micropellets in the Brain' RONALD
D. N A D L E R , Ph.D.
Department of Psychiatry, State University of New York, Downstate Medical Center, Brooklyn, New York (Received 2 June 1969) R. D. An improvedinstrumentfor implanting micropellets in the brain. PHYSIOL.BEHAV.5 (1) 123-124, 1970.An instrument is described for preparing and implanting minute pellets in the brain. It makes possible accurate intracerebral implantation of chemicals without attaching cannulas to the skull. NADLER,
Brain implantation
Chemical stimulation
Stereotaxic
As/'ART of a program involving localized hormone stimulation in the brains of neonatal rats [5] the author developed a technique for making and stereotaxically implanting uniform micropellets of crystalline steroids [4]. The technique is also appropriate for use with adult animals and different species. Its advantage lies in the fact that it avoids the necessity of cementing steroid-containing eannulas to the skull as is done with the more common procedure of intracerebral implantation of steroids [1, 3].
2.
A stylus crimped into a length of 26 ga s/s tubing (Fig. 1B). A small section of 21 ga tubing (bottom retainer) is slipped over the end of the 26 ga tubing before crimping the two. The bottom retainer and a second retainer that
A.
B.
C. tubing
Further work with the implanting technique has led to modification of the implanting instrument, designed to increase the reliability of implanting pellets at a desired depth within the brain. The basic procedure in making micropellets involves tamping a substance into a needle that has been cut flat at the tip. The original instrument contained a stylus for ejecting the pellet which could only be extruded. The modified instrument (Fig. 1) contains a stylus that can be retracted as well as extruded. Retracting the stylus, after the pellet has been ejected, breaks the contact between the stylus and the pellet. Therefore, retracting, rotating and extruding the stylus a few times while the instrument is in the brain decreases the probability of withdrawing the pellet when the instrument is withdrawn from the brain. Articles describing experiments in which similar types of pellets have been used have not described the implanting instruments in sufficient detail to allow others to construct them [2, 6-8].
~
The modified instrument consists of three parts: 1. A 1 cm s syringe with a guide cemented in it (Fig. 1A). The guide is a length of 21 ga stainless steel (s/s) tubing. A plastic disposable syringe is preferred to a glass one because it doesn't break.
syringe
26 go. IT 'ubing
I~
0.75ram. c[eoronce FIG. 1. Micropellet implanting tool.
1The implanting instrument was developed during tenure of USPHS postdoctoral fellowship 1-F2-HD-29,015-02. 123
124
NADI,t bl may be crimped to the other end of the 26 ga tubing control the excursion of the stylus.
3.
A 26 ga hypodermic needle, cut fiat at the tip, as described in the earlier article [2].
The 26 ga tubing with stylus crimped into it is inserted into the guide in the syringe. The 26 ga needle is slipped over the stylus and attached to the syringe in the usual manner. By adjusting the lengths of the bottom retainer (section of 21 ga tubing), the stylus, and the 26 ga needle it is possible to construct an instrument that functions both in making and implanting micropellets. For example, if the length of the
bottom retainer is such that it permits the stylus to travci 1.25 ram, it is possible to prepare 0.5 mm pellets which when ejected, extend 0.75 mm beyond the tip of tile needle (Fig. IC). While the instrument described makes pellets formed in a 26 ga needle, needles, tubing and styli of other sizes can be used in a similar manner to make pellets of other sizes. The micropellets are made by retracting the stylus and tamping the needle into a substance to be implanted. Then the needle is wiped clean, the instrument is attached to the verticle drive of a stercotaxic instrument with an appropriate clamping device and standard stereotaxic procedures arc followed for implanting the pellet in the brain.
REFERENCES
1. Harris, G. W., R. P. Michael and P. P. Scott. Neurological site of action of stilbesterol in eliciting sexual behavior. CibaFoundn. Symp. Neurol. Basis Behav. 236-254, 1958. 2. Levine, S., H. M. Zimmerman, E. J. Wenk and N. R. Gonatas. Experimental leukoencephalopathies due to implantation of foreign substances. Am. J. Pathol. 42:97-117, 1963. 3. Lisk, R. D. Estrogen-sensitive centers in the hypothalamus of the rat. J. exp. Zool. 145: 197-208, 1960. 4. Nadler, R. D. Preparation and implantation of minute pellets in the brain of the neonatal rat. Electroenceph. clin. Neurophysiol. 23: 74--76, 1967.
5. Nadler, R. D. Masculinization of female rats by intracranial implantation of androgen in infancy. J. eomp. physiol. PsychoL 66: 157-167, 1968. 6. Smelik, P. G. ACTH secretion after depletion of hypothalamic monoamines by reserpine implants. Neuroendocrinology 2: 247-254, 1967. 7. Smith, E. R. and J. M. Davidsoq. Differential responses to hypothalamic testosterone in relation to male puberty. Am. J. Physiol. 212: 1385-1390, 1967. 8. Wagner, J. W., W. Erwin and V. Critchlow. Androgen sterilization produced by intracerebral implants of testosterone in neonatal female rats. Endocrinology 79: 1135-I 142, 1966.
BRIEF COMMUNICATION An Improved Instrument for Implanting Micropellets in the Brain' RONALD
D. N A D L E R , Ph.D.
Department of Psychiatry, State University of New York, Downstate Medical Center, Brooklyn, New York (Received 2 June 1969) R. D. An improvedinstrumentfor implanting micropellets in the brain. PHYSIOL.BEHAV.5 (1) 123-124, 1970.An instrument is described for preparing and implanting minute pellets in the brain. It makes possible accurate intracerebral implantation of chemicals without attaching cannulas to the skull. NADLER,
Brain implantation
Chemical stimulation
Stereotaxic
As/'ART of a program involving localized hormone stimulation in the brains of neonatal rats [5] the author developed a technique for making and stereotaxically implanting uniform micropellets of crystalline steroids [4]. The technique is also appropriate for use with adult animals and different species. Its advantage lies in the fact that it avoids the necessity of cementing steroid-containing eannulas to the skull as is done with the more common procedure of intracerebral implantation of steroids [1, 3].
2.
A stylus crimped into a length of 26 ga s/s tubing (Fig. 1B). A small section of 21 ga tubing (bottom retainer) is slipped over the end of the 26 ga tubing before crimping the two. The bottom retainer and a second retainer that
A.
B.
C. tubing
Further work with the implanting technique has led to modification of the implanting instrument, designed to increase the reliability of implanting pellets at a desired depth within the brain. The basic procedure in making micropellets involves tamping a substance into a needle that has been cut flat at the tip. The original instrument contained a stylus for ejecting the pellet which could only be extruded. The modified instrument (Fig. 1) contains a stylus that can be retracted as well as extruded. Retracting the stylus, after the pellet has been ejected, breaks the contact between the stylus and the pellet. Therefore, retracting, rotating and extruding the stylus a few times while the instrument is in the brain decreases the probability of withdrawing the pellet when the instrument is withdrawn from the brain. Articles describing experiments in which similar types of pellets have been used have not described the implanting instruments in sufficient detail to allow others to construct them [2, 6-8].
~
The modified instrument consists of three parts: 1. A 1 cm s syringe with a guide cemented in it (Fig. 1A). The guide is a length of 21 ga stainless steel (s/s) tubing. A plastic disposable syringe is preferred to a glass one because it doesn't break.
syringe
26 go. IT 'ubing
I~
0.75ram. c[eoronce FIG. 1. Micropellet implanting tool.
1The implanting instrument was developed during tenure of USPHS postdoctoral fellowship 1-F2-HD-29,015-02. 123
124
NADI,t bl may be crimped to the other end of the 26 ga tubing control the excursion of the stylus.
3.
A 26 ga hypodermic needle, cut fiat at the tip, as described in the earlier article [2].
The 26 ga tubing with stylus crimped into it is inserted into the guide in the syringe. The 26 ga needle is slipped over the stylus and attached to the syringe in the usual manner. By adjusting the lengths of the bottom retainer (section of 21 ga tubing), the stylus, and the 26 ga needle it is possible to construct an instrument that functions both in making and implanting micropellets. For example, if the length of the
bottom retainer is such that it permits the stylus to travci 1.25 ram, it is possible to prepare 0.5 mm pellets which when ejected, extend 0.75 mm beyond the tip of tile needle (Fig. IC). While the instrument described makes pellets formed in a 26 ga needle, needles, tubing and styli of other sizes can be used in a similar manner to make pellets of other sizes. The micropellets are made by retracting the stylus and tamping the needle into a substance to be implanted. Then the needle is wiped clean, the instrument is attached to the verticle drive of a stercotaxic instrument with an appropriate clamping device and standard stereotaxic procedures arc followed for implanting the pellet in the brain.
REFERENCES
1. Harris, G. W., R. P. Michael and P. P. Scott. Neurological site of action of stilbesterol in eliciting sexual behavior. CibaFoundn. Symp. Neurol. Basis Behav. 236-254, 1958. 2. Levine, S., H. M. Zimmerman, E. J. Wenk and N. R. Gonatas. Experimental leukoencephalopathies due to implantation of foreign substances. Am. J. Pathol. 42:97-117, 1963. 3. Lisk, R. D. Estrogen-sensitive centers in the hypothalamus of the rat. J. exp. Zool. 145: 197-208, 1960. 4. Nadler, R. D. Preparation and implantation of minute pellets in the brain of the neonatal rat. Electroenceph. clin. Neurophysiol. 23: 74--76, 1967.
5. Nadler, R. D. Masculinization of female rats by intracranial implantation of androgen in infancy. J. eomp. physiol. PsychoL 66: 157-167, 1968. 6. Smelik, P. G. ACTH secretion after depletion of hypothalamic monoamines by reserpine implants. Neuroendocrinology 2: 247-254, 1967. 7. Smith, E. R. and J. M. Davidsoq. Differential responses to hypothalamic testosterone in relation to male puberty. Am. J. Physiol. 212: 1385-1390, 1967. 8. Wagner, J. W., W. Erwin and V. Critchlow. Androgen sterilization produced by intracerebral implants of testosterone in neonatal female rats. Endocrinology 79: 1135-I 142, 1966.