letter Neuroanatomical nomenclature SIR:

We were pleased to read Butcher and Semba's report 'Reassessing the cholinergic basal forebrain: nomenclature schemata and concepts '1. There is a critical need for a stable neuroanatomical nomenclature to convey information between neuroscientists accurately and intelligibly. In some areas of the brain, such as the cortex, there is such a multitude of synonyms that researchers need to use a table of equivalence of the different terms. Unfortunately, N o m i n a A n a t o m i c a 2 does not provide a comprehensive list of terms for

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the nervous system. For example, it lists three amygdaloid nuclei, while de Olmos eta/. 3 recognize 51. The initiative shown by Butcher and Semba and your willingness to publish their work will be welcome to those who find the proliferation of synonyms, and abbreviations thereof, an unnecessary obstacle to understanding. As cartographers, we are at times in the unenviable position of deciding between competing nomenclature schemes. Attention to nomenclature by the primary researchers in the area as well as by editors of journals should assist in arriving at a consensus. It should always be remem-

to

the

editor

bered that sharing nomenclature with others presents no risk of infection by communicative diseases. George Paxino$ Istvan T6rk Schools of Psychologyand Anatomy, The Universityof New South Wales,PC)Box 1, Kensington, NSW,Australia2033.

References 1 Butcher, L. L. and Semba, K. (1989) Trends NeuroscL 12,483-485 2 Anon. (1983) Nomina Anatomica (5th

edfT; 11th International Congress of Anatomists) Williams and Wilkins 3 de OImos, J., Alheid, G. F. and Beltramino, C. A. (1985) in The Rat

Nervous System VoL 1: Forebrain and Midbrain (Paxinos, G., ed.), pp. 223-334, Academic Press

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reviews

Ion condudancesaffectedby 5-HT receptorsubtypesin mammalianneurons Daniel H. Bobker and John T. Williams

5-Hydroxytryptamine (5-HT) has both excitatory and 5-HT caused a hyperpolarization of CA1 hippocampal inhibitory actions in the CNS and PNS. The develop- neurons. 8-OH-DPAT was a weak partial agonist (at ment of new 5-HT ligands has led to the expansion of micromolar concentrations) in one study 7 and an 5-HT receptor subtypes into three categories: 5-HT1, antagonist (at nanomolar concentrations) in the other s 5-HT2 and 5-1-17"3 (Ref 1). Each category has further indicating that there is an absence of 'spare' receptors subdivisions. The literature concerning the biochemical in the hippocampus. Both studies found that the basis of this division has been reviewed recently2. While 5-HT1n-mediated hyperpolarization was a result of an this approach has elucidated many of the pharmaco- increased conductance to potassium (K +) ions. Furlogical properties of 5-HT receptors, it has not addressed thermore, the K + current induced by 5-HT was the question of how 5-HT modulates cell excitability. blocked by pretreatment of the animal with pertussis Physiological studies have confirmed the existence of a toxin. The 5-HT1A receptor has therefore been mul@licity of 5-HT receptors that act through a variety included in the growing list of receptors that cause an of ionic mechanisms. The purpose of this review is to increase in K + conductance mediated by a pertussis summarize what is known of the ionic mechanisms toxin-sensitive G protein 9-n. A 5-HT-mediated hyperpolarization has also been associated with the activation of identified mammalian 5-HT receptor subtypes, as well as some effects of 5-HT reported in neurons of the dorsal raphe 12,13 (Fig. 1A), prepositus hypoglossi14, superior cervical ganglion 15, where the receptor could not be defined. and myenteric plexus TM. Additionally, a 5-HTmediated inhibitory postsynaptic potential (IPSP) has Increase in potassium conductance: 5-HTIA The 5-HTIA receptor has been localized throughout been reported in rat dorsal raphe 12,1s and in guineathe nervous system, with high concentrations in limbic pig prepositus hypoglossiTM neurons. As would be regions and in the dorsal raphe nucleus 3 (Table I). expected for a response mediated by the activation of Interest in this site has developed since the discovery 5-HT~A receptors, these IPSPs were blocked by of the selective 5-HTIA agonist, 8-hydroxy-(2-N,N- nanomolar concentrations of spiperone, prolonged by dipropylamino)-tetraline (8-OH-DPAT) 4. Unfortu- fluoxetine or cocaine (Fig. 1B,C), and reversed nately, in physiological studies, this compound can act polarity at the K + equilibrium potential 12,14,17,18. The as a full agonist, a partial agonist, or an antagonist time-course of the synaptic potential was slow (and depending on the receptor reserve of the tissue. similar in the two preparations), with a 1-2 s duration, Nevertheless, when used at concentrations under and so is comparable to the noradrenergic IPSP 1 ~w and in combination with the antagonist spiperone 5,6, mediated by oc2-adrenoceptors in the locus coeruleus 19 8-OH-DPAT identifies 5-HT~A receptor-mediated and the GABAB-mediated IPSP in the hippocampus 2°. actions. A remaining question concerning the 5-HT1A recepReports from two laboratories demonstrated that tor is the role of adenylate cyclase. Both stimulation of TINS, Vol. 13, No. 5, 1990

© 1990, EPsevieScience r PublishersLtd,(UK) 0166- 2236/90/$02.00

DanielH. Bobkerand John T. Williamsare at the Vollum Institute, Oregon HealthScience University,3181SW SamJacksonPark Road,Portland,OR 97201, USA.

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Neuroanatomical nomenclature.

letter Neuroanatomical nomenclature SIR: We were pleased to read Butcher and Semba's report 'Reassessing the cholinergic basal forebrain: nomenclatur...
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