Blue Peter stretch of track which, on 3 July 1938, saw the world speed record for steam locomotives of set by LNER A4 Locomotive no. 4468 "Mallard". In October 1998, Richard Bacon was sacked, following reports in "News of the World" that he had taken cocaine. This incident followed shortly after the show's 40th anniversary, when previous presenters returned for a special programme. Those returning included Leila Williams, Valerie Singleton, John Noakes, Peter Purves, Diane Louise Jordan, Anthea Turner, John Leslie, Tim Vincent, Yvette Fielding, Caron Keating, Mark Curry, Janet Ellis, Peter Duncan, Sarah Greene, Tina Heath, Simon Groome and Christopher Wenner.
Cocaine in rats with ratios of about: serotonin:dopamine = 2:3, serotonin:norepinephrine = 2:5). The most extensively studied effect of cocaine on the central nervous system is the blockade of the dopamine transporter protein. Dopamine transmitter released during neural signaling is normally recycled via the transporter; i.e., the transporter binds the transmitter and pumps it out of the synaptic cleft back into the presynaptic neuron, where it is taken up into storage vesicles. Cocaine binds tightly at the dopamine transporter forming a complex that blocks the transporter's function. The dopamine transporter can no longer perform its reuptake function, and thus dopamine accumulates