Differential actions of the blockade of spinal opioid, adrenergic and serotonergic receptors on the tail-flick inhibition induced by morphine microinjected into dorsal raphe and central gray in rats

Microinjection of morphine sulfate into dorsal raphe, ventrolateral central gray and dorsolateral central gray inhibits spinal nociceptive reflexes. The effects of the blockade of spinal opioid, adrenergic, and serotonergic receptors by intrathecal injection of naloxone, yohimbine and methysergide, respectively, on inhibition of the tail-flick response induced by morphine microinjected into dorsal raphe, ventrolateral central gray and dorsolateral central gray were studied. Naloxone (20 micrograms) given intrathecally effectively antagonized inhibition of the tail-flick response induced by morphine (4 micrograms) given into dorsal raphe and ventrolateral central gray, but not dorsolateral central gray. On the other hand, intrathecal injection of yohimbine (30 micrograms) antagonized inhibition of the tail-flick response induced by morphine given into ventrolateral central gray and dorsolateral central gray, but not dorsal raphe. Intrathecal injection of prazosin (30 micrograms) did not antagonize inhibition of the tail-flick response induced by morphine given into dorsal raphe or lateral central gray. Intrathecal injection of methysergide (30 micrograms) only partially antagonized inhibition of the tail-flick response induced by morphine given into dorsal raphe, but not ventrolateral central gray and dorsolateral central gray. It is concluded that the analgesia induced by morphine injected into dorsal raphe is mediated by spinal opioid receptors but not by spinal alpha 2-adrenergic receptors while the analgesia produced by morphine given into dorsolateral central gray is mediated by spinal alpha 2-adrenergic receptors. The analgesia induced by morphine given into ventrolateral central gray is mediated in part by both spinal alpha 2-adrenergic and opioid receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Atypical spasmus nutans as an initial sign of thalamic neoplasm

A patient is described who presented with dissociated nystagmus (atypical spasmus nutans) and an underlying pulvinar-tectal lesion. Atypical spasmus nutans is discussed and clinicians are alerted to a spectrum of possible etiologies.

Acute monocytic leukemia recurring as bilateral perilimbal infiltrates. Immunohistochemical and ultrastructural confirmation

A 28-year-old woman developed leukopenia and slight cervical lymphadenopathy. Bone marrow aspiration and special stains established the diagnosis of acute monocytic leukemia. Following chemotherapy a complete hematologic remission was elicited. Seven months later, she consulted an ophthalmologist because of bilateral conjunctival lesions. Ophthalmologic examination showed subconjunctival, perilimbal grayish-pink infiltrates. A conjunctival biopsy disclosed sheets of mononuclear cells consistent with acute monocytic leukemia. Four months later, she developed cutaneous lesions in the face and chest wall. Subsequent biopsies of conjunctiva and skin and immunohistochemical demonstration of muramidase in the tumor cells supported the diagnosis of monocytic leukemia. Electron microscopic studies were particularly valuable and disclosed that more than 80% of the leukemic cells contained two types of cytoplasmic complexes of rough endoplasmic reticulum that displayed both tubular and helical configurations. These complexes differed morphologically from the ribosome-lamellar complexes observed in hairy cell leukemia and other hematologic disorders.